Add API tests for format2-to-native conversion artifacts

[jmchilton]

Verify Galaxy correctly executes workflows whose tool_state contains representation differences from schema-unaware gxformat2 conversion.

Workflow tests cover list-form multiple selects, absent all-None sections, absent empty repeats with and without corrections, a safe-template empty repeat, lowercase JSON booleans, and connection-only section omission. Test data lives in wf_conversion/ with frozen native .ga snapshots and available format2 sources.

Tool execution tests cover explicit empty repeat, absent repeat, repeat instances, and list-form multiple select handling across legacy, 21.01, and request input formats.

Duplication check:

• No exact existing Galaxy test already imports native .ga workflows with gxformat2 conversion-artifact tool_state and executes them.

• Multiple-select coverage is adjacent to existing multi_select workflow/tool tests, but those use normal format2/tool execution paths rather than list-encoded native workflow tool_state.

• Boolean coverage is adjacent to gx_boolean tool tests for JSON booleans, but those do not cover native workflow execution from converted .ga tool_state.

• Repeat coverage is adjacent to existing repeat tools and API tests, but existing tests either require instances, index the first repeat item, or cover min-filled repeats; they do not cover omitted repeat keys in native workflow tool_state.

• The two absent-empty-repeat workflow tests intentionally overlap except for allow_tool_state_corrections, documenting that the flag does not change the current failure mode.

• The connection-only section test is not duplicated elsewhere; it covers omitted section state resolved through input_connections.

The empty_repeat_optional fixture is documented as native-only because wf_tool_state does not contain a companion format2 source.

(cherry picked from commit ef93b9f in #22996)

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.