Add change file for prerelease and run formatting checks

Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com>

Author: Copilot

change/1756980197-fix-deadlock.json

@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "Fix deadlock in ReactInstanceWin::DetachRootView by replacing sync call with async",
+  "packageName": "react-native-windows",
+  "email": "copilot@github.com",
+  "dependentChangeType": "patch"
+}