feat(logpush): regenerate SDK and add comprehensive integration tests

[anaghajoshiibm]

PR summary

Fixes "unexpected EOF" error when retrieving logpush jobs configured with custom HTTP destinations. Optional fields in LogpushJobPack struct had incorrect validate:"required" tags, causing unmarshaling to fail when API returned null values.

Fixes: https://github.ibm.com/NetworkTribe/CIS_Support/issues/5296

PR Checklist

Please make sure that your PR fulfills the following requirements:

• The commit message follows the Angular Commit Message Guidelines.
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• New tests
• Build/CI related changes
• Documentation content changes
• Other (please describe)

What is the current behavior?

SDK fails to parse API responses for logpush jobs with custom HTTP destinations when optional fields (last_complete, last_error, error_message) contain null values. Error: "unexpected EOF" with HTTP 200 status code.

What is the new behavior?

SDK correctly handles null values in optional fields. Logpush jobs with custom HTTP destinations can be retrieved without errors. Fields are properly marked as optional with omitempty JSON tags instead of validate:"required".

Does this PR introduce a breaking change?

• Yes
• No

Other information

• Regenerated SDK with IBM OpenAPI SDK Generator v3.114.0
• All unit tests pass
• No changes to public API surface
• Backward compatible with existing code
• Related: https://github.ibm.com/NetworkTribe/ui-cli-sdk-terraform-netserv/issues/565