Cherry-pick: remove "Upgrade App Manifest" command and fix Advanced DA error message

[Copilot]

Cherry-pick of PR #15413 (fix: "upgrade manifest" and advanced da error message) from release/6.6 to dev.

Changes

• fx-core/resource/package.nls.json — Updated SharedScopeAdvancedDADisabled error message to clarify the restriction is specific to 'shared' scope and replaced the verbose Microsoft Learn link title with "Known limitation of Advanced Declarative Agent"
• vscode-extension/package.json — Removed the fx-extension.migrateTeamsManifest command registration ("Upgrade App Manifest")
• vscode-extension/package.nls.json — Removed the teamstoolkit.commands.migrateManifest.title string
• vscode-extension/src/extension.ts — Removed migrateTeamsManifestHandler import, setupMCPServer import, and the migrateTeamsManifest command subscription

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Cherry-pick] PR #15413 needs to be synchronized to other branches</issue_title>
<issue_description>

Cherry-pick Reminder

@tecton Hello!

This is an automatically created reminder. Your PR #15413 (fix: "upgrade manifest" and advanced da error message) is being merged into the release/6.6 branch.

Please ensure to cherry-pick these changes to the following branches:

• cherry-pick fix: "upgrade manifest" and advanced da error message #15413 to dev
• cherry-pick fix: "upgrade manifest" and advanced da error message #15413 to release/vs1714p7

Steps to Follow:

1. Wait for the current PR to be merged.
2. Execute the following commands locally:

   git fetch origin
   git checkout <target_branch>
   git cherry-pick <commit_hash>
   git push origin <target_branch>

3. Or create a new PR to merge these changes into the above branches.

After completion, please check the items above ✓

Note: This is an automatically created issue. You can close this issue after completing all the operations.
</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Cherry-pick] PR #15413 needs to be synchronized to other branches #15440

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