fix(template): cherry-pick supportsChannelFeatures field fixes to dev

[Copilot]

Cherry-pick of #15371 — removes supportsChannelFeatures from devPreview manifests where it's invalid, and upgrades stale v1.23 manifest schemas to v1.25.

Changes

• Remove supportsChannelFeatures: "tier1" from devPreview manifests:

  • declarative-agent-meta-os-new-project/appPackage/manifest.json.tpl
  • office-addin-excel-cfshortcut/appPackage/manifest.json.tpl
  • office-addin-wxpo-taskpane/appPackage/manifest.json.tpl

• Upgrade manifest schema v1.23 → v1.25:

  • python/basic-custom-engine-agent/appPackage/manifest.json.tpl
  • python/weather-agent/appPackage/manifest.json.tpl

ts/foundry-agent was already at v1.25 with supportsChannelFeatures in the dev branch — no change needed.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Cherry-pick] PR #15371 needs to be synchronized to other branches</issue_title>
<issue_description>

Cherry-pick Reminder

@tecton Hello!

This is an automatically created reminder. Your PR #15371 (fix(template): supportsChannelFeatures field) is being merged into the release/6.5 branch.

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

• cherry-pick fix(template): supportsChannelFeatures field #15371 to dev
• cherry-pick fix(template): supportsChannelFeatures field #15371 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 #15371 needs to be synchronized to other branches #15373

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.30%. Comparing base (785ee1d) to head (80865df).
⚠️ Report is 23 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev   #15384      +/-   ##
==========================================
+ Coverage   89.29%   89.30%   +0.01%     
==========================================
  Files         620      620              
  Lines       38065    38065              
  Branches     7555     7541      -14     
==========================================
+ Hits        33989    33994       +5     
+ Misses       1973     1969       -4     
+ Partials     2103     2102       -1     

see 1 file with indirect coverage changes

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