[Feature] remove redundant onCommand activation event covered by VS Code auto-generation

[EmmaYuan1015]

Summary

package.json contains a redundant onCommand activation event entry:

Background

Since VS Code 1.74.0, all commands declared in contributes.commands automatically have their corresponding onCommand activation events generated by VS Code — no manual entry in activationEvents is needed release notes.

This extension requires engines.vscode >= 1.75.0, and reactNative.cleanRestartPackager is already declared in contributes.commands, making this entry purely redundant.

Changes

Remove "onCommand:reactNative.cleanRestartPackager" from activationEvents
Impact
No functional change — behavior is identical to before
Reduces maintenance noise and keeps activationEvents limited to entries that cannot be auto-generated