tsp - Add clientname support for body parameter

[dolauli]

This pull request introduces enhancements to the PowerShell TypeSpec converter, primarily focusing on improving client name handling and schema generation, along with minor cleanup in test directories. The most significant changes involve using client name overrides for parameters and models, refining schema generation for union and record types, and updating imports to support these features.

Client name override improvements

• Updated parameter creation in convertor.ts to use getClientNameOverride for body parameters, ensuring that client-specific naming conventions are respected.
• Enhanced model schema generation in modelUtils.ts to utilize getClientNameOverride for models, improving consistency in client-facing names.

Schema generation enhancements

• Improved union type schema handling in modelUtils.ts to correctly process record models named "Record", ensuring accurate schema output for these cases.

Dependency and import updates

• Added getClientNameOverride to imports from @azure-tools/typespec-client-generator-core in modelUtils.ts, enabling the new naming logic.

Test directory cleanup

• Removed unnecessary files and patterns from .gitignore in tests-emitter/AppComplianceAutomation.Management/target and tests-emitter/Sphere.Management/target, streamlining test output management.