feat(stepfunctions): Enable execution details page

[l0minous]

Problem

View Execution Details by Execution ARN command currently only opens a placeholder Hello World webview instead of an Execution Details page.

Solution

• Modify workflowStudioApiHandler.ts into StepFunctionApiHandler.ts as well adding ability to perform Api calls for execution detail specific APIs
• Updating types.ts , stepFunctions.ts (in clients folder) , executionDetailProvider.ts to support new API calls and sdk v3
• Implementing separate handleMessage.ts to handle messaging between Execution Details webview and toolkit

Verification

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[github-actions]

• This pull request modifies code in src/* but no tests were added/updated.
  • Confirm whether tests should be added or ensure the PR description explains why tests are not required.

[github-actions]

• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
  • Note: beta or "experiment" features that have active users should announce fixes in the changelog.
  • If this is not a feature or fix, use an appropriate type from the title guidelines. For example, telemetry-only changes should use the telemetry type.