chore(NA): add missing branches into backportrc configuration file (#79848)

* chore(NA): add missing branches into backportrc configuration file

* chore(NA): fix extra line for defined regexs

Author: mistic

.backportrc.json

@@ -3,6 +3,7 @@
   "targetBranchChoices": [
     { "name": "master", "checked": true },
     { "name": "7.x", "checked": true },
+    "7.10",
     "7.9",
     "7.8",
     "7.7",
@@ -27,7 +28,7 @@
   "targetPRLabels": ["backport"],
   "branchLabelMapping": {
     "^v8.0.0$": "master",
-    "^v7.10.0$": "7.x",
+    "^v7.11.0$": "7.x",
     "^v(\\d+).(\\d+).\\d+$": "$1.$2"
   }
 }