fix: [2.5][GoSDK] move metaheader to client in case of race

[congqixia]

Cherry-pick from master
pr: #40443
See failure run in #40352

This PR:

• move metaheader map to client struct from config
• set default value for field schema

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: congqixia

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[mergify]

@congqixia Thanks for your contribution. Please submit with DCO, see the contributing guide https://github.com/milvus-io/milvus/blob/master/CONTRIBUTING.md#developer-certificate-of-origin-dco.

[ThreadDao]

/lgtm

[codecov]

Codecov Report

Attention: Patch coverage is 43.75000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 80.94%. Comparing base (54a2509) to head (41ea3cb).
Report is 7 commits behind head on 2.5.

Files with missing lines	Patch %	Lines
client/milvusclient/client.go	33.33%	6 Missing and 2 partials ⚠️
client/milvusclient/interceptors.go	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              2.5   #40444      +/-   ##
==========================================
+ Coverage   80.92%   80.94%   +0.02%     
==========================================
  Files        1419     1419              
  Lines      200489   200491       +2     
==========================================
+ Hits       162242   162293      +51     
+ Misses      32579    32537      -42     
+ Partials     5668     5661       -7     

Components	Coverage Δ
Client	79.77% <43.75%> (+0.04%)	⬆️
Core	70.17% <ø> (ø)
Go	82.85% <ø> (+0.02%)	⬆️

Files with missing lines	Coverage Δ
client/entity/field.go	59.09% <100.00%> (+0.47%)	⬆️
client/milvusclient/client_config.go	39.58% <ø> (+4.58%)	⬆️
client/milvusclient/interceptors.go	59.30% <0.00%> (ø)
client/milvusclient/client.go	56.73% <33.33%> (-2.50%)	⬇️

... and 30 files with indirect coverage changes

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