Remove json dependency for net9

[apoorvdeshmukh]

Description

Remove incorrect dependency System.Text.Json from nuspec file for .NET9

Keeping the nuspec aligned with this output

\git\SqlClient>dotnet list src\Microsoft.Data.SqlClient\netcore\src package
Project 'Microsoft.Data.SqlClient' has the following package references
   [net8.0]:
   Top-level Package                                         Requested    Resolved
   > Azure.Identity                                          1.14.2       1.14.2
   > Microsoft.Bcl.Cryptography                              8.0.0        8.0.0
   > Microsoft.Data.SqlClient.SNI.runtime                    6.0.2        6.0.2
   > Microsoft.Extensions.Caching.Memory                     8.0.1        8.0.1
   > Microsoft.IdentityModel.JsonWebTokens                   7.5.0        7.5.0
   > Microsoft.IdentityModel.Protocols.OpenIdConnect         7.5.0        7.5.0
   > Microsoft.NET.ILLink.Tasks                        (A)   [8.0.22, )   8.0.22
   > Microsoft.SqlServer.Server                              1.0.0        1.0.0
   > System.Configuration.ConfigurationManager               8.0.1        8.0.1
   > System.Security.Cryptography.Pkcs                       8.0.1        8.0.1

   [net9.0]:
   Top-level Package                                         Requested    Resolved
   > Azure.Identity                                          1.14.2       1.14.2
   > Microsoft.Bcl.Cryptography                              9.0.4        9.0.4
   > Microsoft.Data.SqlClient.SNI.runtime                    6.0.2        6.0.2
   > Microsoft.Extensions.Caching.Memory                     9.0.4        9.0.4
   > Microsoft.IdentityModel.JsonWebTokens                   7.5.0        7.5.0
   > Microsoft.IdentityModel.Protocols.OpenIdConnect         7.5.0        7.5.0
   > Microsoft.NET.ILLink.Tasks                        (A)   [9.0.11, )   9.0.11
   > Microsoft.SqlServer.Server                              1.0.0        1.0.0
   > System.Configuration.ConfigurationManager               9.0.4        9.0.4
   > System.Security.Cryptography.Pkcs                       9.0.4        9.0.4

(A) : Auto-referenced package.

\git\SqlClient>dotnet list src\Microsoft.Data.SqlClient\netcore\ref package
Project 'Microsoft.Data.SqlClient' has the following package references
   [net8.0]:
   Top-level Package                                      Requested   Resolved
   > Azure.Identity                                       1.14.2      1.14.2
   > Microsoft.Bcl.Cryptography                           8.0.0       8.0.0
   > Microsoft.Data.SqlClient.SNI.runtime                 6.0.2       6.0.2
   > Microsoft.Extensions.Caching.Memory                  8.0.1       8.0.1
   > Microsoft.IdentityModel.JsonWebTokens                7.5.0       7.5.0
   > Microsoft.IdentityModel.Protocols.OpenIdConnect      7.5.0       7.5.0
   > Microsoft.SqlServer.Server                           1.0.0       1.0.0
   > System.Configuration.ConfigurationManager            8.0.1       8.0.1
   > System.Security.Cryptography.Pkcs                    8.0.1       8.0.1

   [net9.0]:
   Top-level Package                                      Requested   Resolved
   > Azure.Identity                                       1.14.2      1.14.2
   > Microsoft.Bcl.Cryptography                           9.0.4       9.0.4
   > Microsoft.Data.SqlClient.SNI.runtime                 6.0.2       6.0.2
   > Microsoft.Extensions.Caching.Memory                  9.0.4       9.0.4
   > Microsoft.IdentityModel.JsonWebTokens                7.5.0       7.5.0
   > Microsoft.IdentityModel.Protocols.OpenIdConnect      7.5.0       7.5.0
   > Microsoft.SqlServer.Server                           1.0.0       1.0.0
   > System.Configuration.ConfigurationManager            9.0.4       9.0.4
   > System.Security.Cryptography.Pkcs                    9.0.4       9.0.4

[Copilot]

Pull Request Overview

This PR removes an incorrect dependency on System.Text.Json from the .NET 9.0 dependency group in the NuGet package specification file.

• Aligns .NET 9 dependencies with .NET 8, which already had this dependency removed in PR #2930
• Removes unnecessary dependency since System.Text.Json is part of the .NET shared framework for .NET 8+ and doesn't need to be explicitly referenced

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.78%. Comparing base (1542afd) to head (bcf227f).
⚠️ Report is 1 commits behind head on release/6.0.

Additional details and impacted files

@@               Coverage Diff               @@
##           release/6.0    #3767      +/-   ##
===============================================
+ Coverage        75.51%   75.78%   +0.26%     
===============================================
  Files              244      244              
  Lines            40212    40221       +9     
===============================================
+ Hits             30368    30482     +114     
+ Misses            9844     9739     -105     

Flag	Coverage Δ
addons	92.58% <ø> (ø)
netcore	75.65% <ø> (+0.26%)	⬆️

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