Update app deploy test to confirm app config changes on redeploy (#2301)

## Changes
Adds additional step to integration test which changes the app config
and confirms it's updated after redeploy

## Tests
```
    helpers_test.go:156: stderr: Deleting files...
    helpers_test.go:156: stderr: Destroy complete!
--- PASS: TestDeployBundleWithApp (470.25s)
PASS
coverage: [no statements]
ok      github.com/databricks/cli/integration/bundle    470.981s        coverage: [no statements]
```

integration/bundle/apps_test.go

@@ -98,6 +98,24 @@ func TestDeployBundleWithApp(t *testing.T) {
   - run
 env:
   - name: JOB_ID
+    value: "%d"`, job.JobId))
+
+	// Redeploy bundle with changed config env for app and confirm it's updated in app.yaml
+	deployBundleWithArgs(t, ctx, root, `--var="env_var_name=ANOTHER_JOB_ID"`, "--force-lock", "--auto-approve")
+	reader, err = wt.W.Workspace.Download(ctx, pathToAppYml)
+	require.NoError(t, err)
+
+	data, err = io.ReadAll(reader)
+	require.NoError(t, err)
+
+	content = string(data)
+	require.Contains(t, content, fmt.Sprintf(`command:
+  - flask
+  - --app
+  - app
+  - run
+env:
+  - name: ANOTHER_JOB_ID
     value: "%d"`, job.JobId))
 
 	if testing.Short() {

integration/bundle/bundles/apps/template/databricks.yml.tmpl

@@ -4,6 +4,10 @@ bundle:
 workspace:
   root_path: "~/.bundle/{{.unique_id}}"
 
+variables:
+  env_var_name:
+    default: "JOB_ID"
+
 resources:
   apps:
     test_app:
@@ -17,7 +21,7 @@ resources:
           - app
           - run
         env:
-          - name: JOB_ID
+          - name: ${var.env_var_name}
             value: ${resources.jobs.foo.id}
 
       resources: