fix: clarify the P2P diagnostic summary label

Call the three latest category observations 'Diagnostic summary' and retain
'Open log' for their event history. Update the primary English message,
status card, and release note together.

Validated with the refactored Commonlib candidate: full checks, 2,063 unit
tests with one skipped, production build, iOS 15 compatibility, and five
Chromium cases. Dependency declarations remain on the published version
until the immutable Commonlib update is available.

src/common/messages/LiveSyncProvisionalMessages.ts

@@ -9,7 +9,7 @@
  * the same change.
  */
 export const liveSyncProvisionalEnglishMessages = {
-    "Diagnostic log": "Diagnostic log",
+    "Diagnostic summary": "Diagnostic summary",
     "Open log": "Open log",
     "Detailed P2P diagnostics and Log Pane output are enabled":
         "Detailed P2P diagnostics and Log Pane output are enabled",