chore(shorebird_cli): remove legacy auth token fallback (#2522)

packages/shorebird_cli/lib/src/auth/auth.dart

@@ -316,19 +316,7 @@ class Auth {
   void _loadCredentials() {
     final envToken = platform.environment[shorebirdTokenEnvVar];
     if (envToken != null) {
-      try {
-        _token = CiToken.fromBase64(envToken);
-      } catch (_) {
-        // TODO(bryanoltman): Remove this legacy behavior after July 2024 or
-        // next major release.
-        logger.warn('''
-$shorebirdTokenEnvVar needs to be updated before the next major release.
-Run `shorebird login:ci` to obtain a new token.''');
-        _token = CiToken(
-          refreshToken: envToken,
-          authProvider: AuthProvider.google,
-        );
-      }
+      _token = CiToken.fromBase64(envToken);
       return;
     }
 

packages/shorebird_cli/lib/src/os/operating_system_interface.dart

@@ -14,6 +14,7 @@ OperatingSystemInterface get osInterface => read(osInterfaceRef);
 /// {@template operating_system_interface}
 /// A wrapper around operating system specific functionality.
 /// {@endtemplate}
+// ignore: one_member_abstracts
 abstract class OperatingSystemInterface {
   /// {@macro operating_system_interface}
   factory OperatingSystemInterface() {

packages/shorebird_cli/test/src/auth/auth_test.dart

@@ -523,14 +523,8 @@ void main() {
           );
         });
 
-        test('prints warning message when token string is not valid base64',
-            () async {
-          auth = buildAuth();
-          verify(
-            () => logger.warn('''
-SHOREBIRD_TOKEN needs to be updated before the next major release.
-Run `shorebird login:ci` to obtain a new token.'''),
-          ).called(1);
+        test('throws error when token string is not valid base64', () async {
+          expect(buildAuth, throwsA(isFormatException));
         });
       });