[ci] Roll Flutter master to 7b850ef (#2991)

* manual roll to first failing hash

* Fix new analyzer warnings

* Update/move some pinned dependencies

Author: stuartmorgan-g

.ci/flutter_master.version

@@ -1 +1 @@
-9102f2fe0bd26db6074ac4a17785296cd341ecb9
+7b850ef3750083212039f1e62b39cb71072e88f3

packages/flutter_migrate/pubspec.yaml

@@ -16,8 +16,6 @@ dependencies:
   meta: 1.8.0
   path: ^1.8.0
   process: 4.2.4
-  test_api: 0.4.13
-  test_core: 0.4.17
   vm_service: 9.3.0
   xml: ^6.1.0
   yaml: 3.1.1
@@ -27,3 +25,4 @@ dev_dependencies:
   file_testing: ^3.0.0
   lints: ^2.0.0
   test: ^1.16.0
+  test_api: ^0.4.13

packages/flutter_migrate/test/base/logger_test.dart

@@ -45,7 +45,7 @@ void main() {
     final WindowsStdoutLogger logger = WindowsStdoutLogger(
       outputPreferences: OutputPreferences.test(),
       stdio: stdio,
-      terminal: Terminal.test(supportsColor: false, supportsEmoji: false),
+      terminal: Terminal.test(),
     );
 
     logger.printStatus('🔥🖼️✗✓🔨💪✏️');

packages/pigeon/lib/cpp_generator.dart

@@ -773,7 +773,7 @@ const flutter::StandardMessageCodec& ${api.name}::GetCodec() {
       final Iterable<String> argNames =
           indexMap(func.arguments, _getSafeArgumentName);
       sendArgument =
-          'flutter::EncodableList { ${(argNames.map((String arg) => 'flutter::CustomEncodableValue($arg)')).join(', ')} }';
+          'flutter::EncodableList { ${argNames.map((String arg) => 'flutter::CustomEncodableValue($arg)').join(', ')} }';
       final String argsSignature =
           map2(argTypes, argNames, (String x, String y) => '$x $y').join(', ');
       indent