Check if the dev branch exists before moving to it.

tasks/general/acct_mgmt/users.yml

@@ -928,8 +928,17 @@
         git ls-remote --heads | sort
 
         if [[ "$base" != "dev" ]]; then
-          echo -e "\n* Switching back to dev."
-          git switch dev
+          git ls-remote --exit-code --heads origin dev
+          dev_exists="$?"
+          if [[ "$dev_exists" == 0 ]]; then
+            echo -e "\n* Switching back to dev."
+            git switch dev
+          elif [[ "$dev_exists" == 2 ]]; then
+            echo -e "\n* Switching back to main."
+            git switch main
+          else
+            echo "*** ERROR: Unknown status for dev_exists, '$dev_exists'. ***"
+          fi
         fi
 
         echo -e "\n* Verifying which branch we're on."