feat(stepfunctions): Enabling text box input to accept Execution ARNs

[l0minous]

Problem

View Execution Details by Execution ARN command currently works only as a button that opens a hardcoded execution ARN

Solution

Modifying View Execution Details by Execution ARN command to now prompt the user to input an Execution ARN which gets passed to ExecutionDetailProvider. Invalid ARNs open a webview displaying The execution ARN is invalid.

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.
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