add display name to request body (not overwrite value null)

[Alexandr-Nedomets]

Describe your changes:

Add display name to request body for Service dto(not overwrite value null)
Fixes
I don't have issue

displayName for service entity rewrite value to null.
how get bug:

1. Edit service entity (fill field display name) and than save
2. Click "connection" and then click "Edit connection" and than click "Save"
   After fix. Bug doesn't repeat
   Please merge change to branch 1.2.5-realese

Type of change:

• Bug fix
• Improvement
• New feature
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation

Checklist:

• I have read the CONTRIBUTING document.
• My PR title is Fixes <issue-number>: <short explanation>
• I have commented on my code, particularly in hard-to-understand areas.
• For JSON Schema changes: I updated the migration scripts or explained why it is not needed.

[github-actions]

Hi there 👋 Thanks for your contribution!

The OpenMetadata team will review the PR shortly! Once it has been labeled as safe to test, the CI workflows
will start executing and we'll be able to make sure everything is working as expected.

Let us know if you need any help!

[github-actions]

Jest test Coverage

UI tests summary

Lines	Statements	Branches	Functions
	56.41% (29251/51856)	37.64% (11750/31214)	36.81% (3498/9502)

[sonarcloud]

Quality Gate passed for 'open-metadata-ui'

Issues
0 New issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud