Use FVM in GitHub Actions and migrate to Flutter 3.32.4 (#641)

* feat: implement Flutter version management using FVM across CI workflows

* Flutter 3.29.3 + minor Package upgrades

* Replace deprecated `withOpacity`

* Upgrade major package versions without breaking changes.

* Disable unnecessary_async rule

Re-enable later

* New language version and automated fixes

- unnecessary_breaks
- unnecessary_underscore

* Update BUILDING.md to use fvm commands

* Add gitignore files for Android and iOS build artifacts

* Migrate iOS dependencies to Swift Package Manager

This is being done automatically by Flutter

* Flutter 3.32.4

* New sdk version

* docs: add IDE setup instructions and troubleshooting guide for FVM integration

lib/api.dart

@@ -593,10 +593,8 @@ class InvenTreeAPI {
             L10().serverAuthenticationError,
             L10().invalidUsernamePassword,
           );
-          break;
         default:
           showStatusCodeError(apiUrl, response.statusCode);
-          break;
       }
 
       debug("Token request failed: STATUS ${response.statusCode}");
@@ -1342,7 +1340,6 @@ class InvenTreeAPI {
                   "responseData": response.data.toString(),
                 }
             );
-            break;
         }
       } else {
 
@@ -1414,7 +1411,6 @@ class InvenTreeAPI {
                 "endpoint": url,
               }
           );
-          break;
       }
 
       showServerError(