Fix gateway compile issues for 2025.3

- Add missing getCoroutineBgContext import
- Add missing kotlinx.coroutines.launch import
- Fixes scope.launch calls in CawsConnectionProvider
- Resolves :plugin-toolkit:jetbrains-gateway:compileKotlin for 2025.3
- BUILD SUCCESSFUL verified

Author: aseemxs

plugins/toolkit/jetbrains-gateway/src/software/aws/toolkits/jetbrains/gateway/CawsConnectionProvider.kt

@@ -37,6 +37,7 @@ import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.launch
 import org.jetbrains.concurrency.AsyncPromise
 import org.jetbrains.concurrency.await
 import software.amazon.awssdk.services.codecatalyst.CodeCatalystClient
@@ -50,6 +51,7 @@ import software.aws.toolkits.core.utils.warn
 import software.aws.toolkits.jetbrains.AwsPlugin
 import software.aws.toolkits.jetbrains.AwsToolkit
 import software.aws.toolkits.jetbrains.core.awsClient
+import software.aws.toolkits.jetbrains.core.coroutines.getCoroutineBgContext
 import software.aws.toolkits.jetbrains.core.credentials.AwsBearerTokenConnection
 import software.aws.toolkits.jetbrains.core.credentials.ToolkitConnectionManager
 import software.aws.toolkits.jetbrains.core.credentials.loginSso