feat(charts): provide more control over helm tests

[schahal]

Motivation

There are times when we need a bit more control over the Pod that's run in helm test. For example:

• Update the image to use a different repository (like a pull-thru cache)
• Disable a test entirely due to a finicky CI or local network
• Should a future test image have a breaking change, we can update args/commands via values as a quick workaround rather than waiting for a new helm release

Changes

This change pulls the defaults into the values.yaml for that control.

Optionally, we can enable/disable any of the tests.

Testing

Ran helm template test . before and after the change and confirmed the rendered templates are the same except for:

• adding an explicit latest tag for the busybox image
• formatting of command/args list

--- /tmp/localstack-orig.yaml	2025-03-07 09:35:10
+++ /tmp/localstack-new.yaml	2025-03-07 09:34:16
@@ -494,9 +494,15 @@
 spec:
   containers:
     - name: wget-edge
-      image: busybox
-      command: ['wget']
-      args: ['-q', '--server-response', '--output-document', '-', 'test-localstack:4566/_localstack/health']
+      image: busybox:latest
+      command:
+        - wget
+      args:
+        - "-q"
+        - "--server-response"
+        - "--output-document"
+        - "-"
+        - "test-localstack:4566/_localstack/health"
   restartPolicy: Never
 ---
 # Source: localstack/templates/tests/test-s3.yaml
@@ -517,7 +523,12 @@
   containers:
     - name: awscli-s3
       image: amazon/aws-cli
-      args: ['--debug', '--endpoint-url', 'http://test-localstack:4566', 's3', 'ls']
+      args:
+        - "--debug"
+        - "--endpoint-url"
+        - "http://test-localstack:4566"
+        - "s3"
+        - "ls"
       env:
       - name: AWS_ACCESS_KEY_ID
         value: test