feat: Cherry-pick PR #15358 — update Teams App Manifest schema to v1.25 (#15364)

* Initial plan

* feat: Update foundry-agent manifest to v1.25 schema with supportsChannelFeatures

Co-authored-by: tecton <886116+tecton@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: tecton <886116+tecton@users.noreply.github.com>

Author: Copilot

templates/vsc/ts/foundry-agent/appPackage/manifest.json.tpl

@@ -1,6 +1,6 @@
 {
-    "$schema": "https://developer.microsoft.com/en-us/json-schemas/teams/v1.24/MicrosoftTeams.schema.json",
-    "manifestVersion": "1.24",
+    "$schema": "https://developer.microsoft.com/en-us/json-schemas/teams/v1.25/MicrosoftTeams.schema.json",
+    "manifestVersion": "1.25",
     "version": "1.0.0",
     "id": "${{TEAMS_APP_ID}}",
     "developer": {
@@ -22,6 +22,7 @@
         "full": "full description for {{appName}}"
     },
     "accentColor": "#FFFFFF",
+    "supportsChannelFeatures": "tier1",
     "copilotAgents": {
         "customEngineAgents": [
             {