fix: missing imports for array of files and date-time parameters

[ricardogrande-masmovil]

This pull request improves the Go code generator to correctly add necessary imports when operations or webhooks use array parameters of binary files or date-time types. It also adds new tests to verify this behavior. The main changes are in the logic for determining imports and in the test coverage. Fixes #22389

Import logic improvements

• Updated AbstractGoCodegen.java to add the "os" import if any parameter is an array of binary files (*os.File), and the "time" import if any parameter is an array of date-time values (time.Time) in both postProcessOperationsWithModels and postProcessWebhooksWithModels methods. [1] [2]

Test coverage

• Added new tests in AbstractGoCodegenTest.java to verify that the "os" import is added for array of binary file parameters and the "time" import is added for array of date-time parameters in operations.
• Included additional imports in the test file to support new test cases.

PR checklist

• Read the contribution guidelines.
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[ricardogrande-masmovil]

Not a java expert at all, so please let me know if I should refactor the tests in any way! :)