fix flutter wallet sdk intro page to show the missing installation and config client instructions (#1711)

Author: christian-rogobete

docs/build/apps/wallet/component/dart/install.mdx

@@ -4,8 +4,8 @@ import { CodeExample } from "@site/src/components/CodeExample";
 
 ```dart
 // pubspec.yaml
-stellar_wallet_flutter_sdk: ^1.0.0
-stellar_flutter_sdk: ^1.8.8
+stellar_wallet_flutter_sdk: ^1.0.6
+stellar_flutter_sdk: ^2.1.3
 ```
 
 </CodeExample>

docs/build/apps/wallet/intro.mdx

@@ -29,7 +29,7 @@ First, you need to add the SDK dependency to your project.
 <LanguageSpecific
   kt={<KtInstall />}
   ts={<TsInstall />}
-  dart={<DartInstall />}
+  flutter={<DartInstall />}
   swift={<SwiftInstall />}
 />
 
@@ -86,7 +86,7 @@ let wallet = Wallet(stellarConfig: StellarConfig.publicNet)
 <LanguageSpecific
   kt={<KtConfigClient />}
   ts={<TsConfigClient />}
-  dart={<DartConfigClient />}
+  flutter={<DartConfigClient />}
 />
 
 ## Stellar Basics