sam: let SAM CLI check for docker

Problem:
The Toolkit does its own check for "is docker running", which breaks
use-cases such as when docker is running on another machine:
#3588

Solution:
Since we surface SAM CLI messages captured by collectSamErrors(), we
don't need to check for Docker.

Author: justinmk3

.changes/next-release/Feature-f3f8fadc-c390-4099-8eff-894b78f4cc58.json

@@ -0,0 +1,4 @@
+{
+	"type": "Feature",
+	"description": "Toolkit no longer explicitly checks if Docker is running, instead it lets SAM CLI decide that #3588"
+}

src/shared/sam/localLambdaRunner.ts

@@ -277,13 +277,6 @@ export async function runLambdaFunction(
     config: SamLaunchRequestArgs,
     onAfterBuild: () => Promise<void>
 ): Promise<SamLaunchRequestArgs> {
-    // Verify if Docker is running
-    const dockerResponse = await new ChildProcess('docker', ['ps'], { logging: 'no' }).run()
-    if (dockerResponse.exitCode !== 0 || dockerResponse.stdout.includes('error during connect')) {
-        throw new ToolkitError('Running AWS SAM projects locally requires Docker. Is it installed and running?', {
-            code: 'NoDocker',
-        })
-    }
     // Switch over to the output channel so the user has feedback that we're getting things ready
     ctx.outputChannel.show(true)
     if (!config.noDebug) {