chore(events-targets): remove experimental dependency (#14537)

A previous [PR](#13823) added a dependency from the stable module `aws-events-targets` to the experimental module `aws-batch`. Depending on experimental modules is no longer allowed.  In fact, this PR build should have failed when attempting to build `aws-cdk-lib`, preventing it from being merged. However, since the dependency was added but not used, the build succeeded, and the PR was merged.

### Why did we expect the PR build of #13823 to fail?

In the build step of `aws-cdk-lib` we strip all the L2 of experimental modules. This means that when compiling `aws-cdk-lib` the L2 types of experimental modules does not exists, if a stable module reference such a type, the build of `aws-cdk-lib` will fail. 

### Why did the PR build of #13823 succeeded?

It added a dependency on the experimental `aws-batch` but didn't use it.

### What are we doing to prevent this from happening in the future?
 #14249 adds a lint rule that disallow depending on an experimental module.


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-events-targets/package.json

@@ -85,7 +85,6 @@
   },
   "dependencies": {
     "@aws-cdk/aws-apigateway": "0.0.0",
-    "@aws-cdk/aws-batch": "0.0.0",
     "@aws-cdk/aws-codebuild": "0.0.0",
     "@aws-cdk/aws-codepipeline": "0.0.0",
     "@aws-cdk/aws-ec2": "0.0.0",
@@ -107,7 +106,6 @@
   "homepage": "https://github.com/aws/aws-cdk",
   "peerDependencies": {
     "@aws-cdk/aws-apigateway": "0.0.0",
-    "@aws-cdk/aws-batch": "0.0.0",
     "@aws-cdk/aws-codebuild": "0.0.0",
     "@aws-cdk/aws-codepipeline": "0.0.0",
     "@aws-cdk/aws-ec2": "0.0.0",