[flutter_conductor] clone from remote upstream, and not local filesystem (#100335)

dev/conductor/core/lib/src/codesign.dart

@@ -73,9 +73,8 @@ class CodesignCommand extends Command<void> {
 
   FrameworkRepository? _framework;
   FrameworkRepository get framework {
-    return _framework ??= FrameworkRepository.localRepoAsUpstream(
+    return _framework ??= FrameworkRepository(
       checkouts,
-      upstreamPath: flutterRoot.path,
     );
   }
 
@@ -113,7 +112,7 @@ class CodesignCommand extends Command<void> {
     } else {
       revision = ((await processManager.run(
         <String>['git', 'rev-parse', 'HEAD'],
-        workingDirectory: (await framework.checkoutDirectory).path,
+        workingDirectory: flutterRoot.path,
       )).stdout as String).trim();
       assert(revision.isNotEmpty);
     }

dev/conductor/core/test/codesign_test.dart

@@ -103,13 +103,18 @@ void main() {
         );
       }
       createRunner(commands: <FakeCommand>[
+        const FakeCommand(command: <String>[
+          'git',
+          'rev-parse',
+          'HEAD',
+        ], stdout: revision),
         const FakeCommand(command: <String>[
           'git',
           'clone',
           '--origin',
           'upstream',
           '--',
-          'file://$flutterRoot/',
+          FrameworkRepository.defaultUpstream,
           '${checkoutsParentDirectory}flutter_conductor_checkouts/framework',
         ]),
         const FakeCommand(command: <String>[
@@ -122,11 +127,6 @@ void main() {
           'rev-parse',
           'HEAD',
         ], stdout: revision),
-        const FakeCommand(command: <String>[
-          'git',
-          'rev-parse',
-          'HEAD',
-        ], stdout: revision),
         const FakeCommand(command: <String>[
           'git',
           'checkout',
@@ -198,7 +198,7 @@ void main() {
           '--origin',
           'upstream',
           '--',
-          'file://$flutterRoot/',
+          FrameworkRepository.defaultUpstream,
           '${checkoutsParentDirectory}flutter_conductor_checkouts/framework',
         ]),
         const FakeCommand(command: <String>[
@@ -291,7 +291,7 @@ void main() {
           '--origin',
           'upstream',
           '--',
-          'file://$flutterRoot/',
+          FrameworkRepository.defaultUpstream,
           '${checkoutsParentDirectory}flutter_conductor_checkouts/framework',
         ]),
         const FakeCommand(command: <String>[
@@ -383,7 +383,7 @@ void main() {
           '--origin',
           'upstream',
           '--',
-          'file://$flutterRoot/',
+          FrameworkRepository.defaultUpstream,
           '${checkoutsParentDirectory}flutter_conductor_checkouts/framework',
         ]),
         const FakeCommand(command: <String>[
@@ -447,7 +447,7 @@ void main() {
           '--origin',
           'upstream',
           '--',
-          'file://$flutterRoot/',
+          FrameworkRepository.defaultUpstream,
           '${checkoutsParentDirectory}flutter_conductor_checkouts/framework',
         ]),
         const FakeCommand(command: <String>[