Update suggested fvm install command

Author: Rexios80

bin/commands.dart

@@ -70,9 +70,11 @@ abstract class Commands {
         // FVM will ask for input from the user, kill the process to avoid
         // hanging
         if (!command.silent) {
+          final version =
+              flutterVersionNotInstalledMatch[1]?.split(' ').last.toLowerCase();
           print(
             red.wrap(
-              'Run `fvm install ${flutterVersionNotInstalledMatch[1]}` first',
+              'Run `fvm install $version` first',
             ),
           );
         }

test/fvm_version_not_installed_test.dart

@@ -4,19 +4,37 @@ import 'package:test/test.dart';
 import 'test_utils.dart';
 
 void main() {
-  test('FVM version not installed', () async {
-    final result = await testCommand(
-      ['get'],
-      entities: {
-        'fvm_version_not_installed_test': {
-          'pubspec.yaml': pubspec('fvm_version_not_installed_test'),
-          '.fvmrc': fvmrc('1.17.0'),
+  group('FVM version not installed', () {
+    test('SDK Version', () async {
+      final result = await testCommand(
+        ['get'],
+        entities: {
+          'fvm_version_not_installed_test': {
+            'pubspec.yaml': pubspec('fvm_version_not_installed_test'),
+            '.fvmrc': fvmrc('1.17.0'),
+          },
         },
-      },
-    );
-    final stdout = result.stdout;
+      );
+      final stdout = result.stdout;
 
-    expect(result.exitCode, isNot(ExitCode.success.code));
-    expectLine(stdout, ['Run `fvm install 1.17.0` first']);
+      expect(result.exitCode, isNot(ExitCode.success.code));
+      expectLine(stdout, ['Run `fvm install 1.17.0` first']);
+    });
+
+    test('Channel', () async {
+      final result = await testCommand(
+        ['get'],
+        entities: {
+          'fvm_version_not_installed_test': {
+            'pubspec.yaml': pubspec('fvm_version_not_installed_test'),
+            '.fvmrc': fvmrc('stable'),
+          },
+        },
+      );
+      final stdout = result.stdout;
+
+      expect(result.exitCode, isNot(ExitCode.success.code));
+      expectLine(stdout, ['Run `fvm install stable` first']);
+    });
   });
 }