Fix module resolution path mismatch in file mode bundler

[Copilot]

JavaScript module requires were failing with Cannot find module '/tmp/gh-aw/scripts/update_activation_comment.cjs' because ScriptsBasePath constant pointed to /opt/gh-aw/scripts while the setup action copies files to /opt/gh-aw/actions.

Changes

• Updated ScriptsBasePath constant to /opt/gh-aw/actions to match SetupActionDestination
• Updated test expectations to reflect correct path

// Before
const ScriptsBasePath = "/opt/gh-aw/scripts"

// After
const ScriptsBasePath = "/opt/gh-aw/actions"  // Must match SetupActionDestination

This ensures file mode workflows correctly resolve require statements at runtime.

Original prompt

Reference: https://github.com/githubnext/gh-aw/actions/runs/21197768976/job/60977520596#step:4:1

Fix Create pull request issue

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