aws-codebuild : secondary source don't seem to register webhook

### Describe the bug

While trying to leverage the ability to attach 2 or more GitHub sources, using `codebuild.Source.git_hub()`, to a project I found that the webhooks in the secondary source array are never registered.

Modifications to the code in the first source will trigger a new build, however nothing will happen if any of the secondary sources are modified.

### Expected Behavior

Because the secondary source array expects a [ISource](https://docs.aws.amazon.com/cdk/api/v2/python/aws_cdk.aws_codebuild/ISource.html#aws_cdk.aws_codebuild.ISource) and I didn't find any documented restrictions, I would have expected the secondary source to behave similar to the primary source : i.e. it would register a webhook with the source and trigger a build when the source is updated.

### Current Behavior

A look at the resulting [Project](https://docs.aws.amazon.com/cdk/api/v2/python/aws_cdk.aws_codebuild/Project.html) in the console shows the secondary source being created as a GitHub source, but a few things seems weird :
* instead of showing "Repository in my GitHub account" as it does for the primary source, the secondary source shows "Public repository"
* the only webhook group configuration presented in the UI is the one for the primary source

I can confirm that the secondary source is properly defined by switching it to being the primary -- in that case the webhook gets registered properly and I receive the notifications from that source.

### Reproduction Steps

Unfortunately don't have a self-contained snippet or something that would work against a public repo but here's a snippet of what I am using :

```
# Source action 1 : will trigger when the buildspec and dockerfile
# for building the target images are modified (primary source)
source1 = codebuild.Source.git_hub(
owner=connection_owner,
repo="source1",
branch_or_ref=branch_source1,
clone_depth=1,
fetch_submodules=False,
report_build_status=True,
webhook=True,
webhook_filters=[
codebuild.FilterGroup.in_event_of(
codebuild.EventAction.PULL_REQUEST_CREATED,
codebuild.EventAction.PULL_REQUEST_UPDATED,
codebuild.EventAction.PULL_REQUEST_REOPENED,
)
.and_base_ref_is(f"^refs/heads/{branch_source1}.*$")
.and_file_path_is("^app/.*$"),
codebuild.FilterGroup.in_event_of(codebuild.EventAction.PUSH)
.and_head_ref_is(f"^refs/heads/{branch_source1}.*$")
.and_file_path_is("^app/.*$"),
],
)

# Source action #2 : will trigger when the app code is modified
source2 = codebuild.Source.git_hub(
owner=connection_owner,
repo="source2",
branch_or_ref=branch_source2,
clone_depth=1,
fetch_submodules=False,
report_build_status=True,
webhook=True,
webhook_filters=[
codebuild.FilterGroup.in_event_of(codebuild.EventAction.PUSH).and_head_ref_is(
f"^refs/heads/{branch_source2}.*$"
),
codebuild.FilterGroup.in_event_of(
codebuild.EventAction.PULL_REQUEST_CREATED,
codebuild.EventAction.PULL_REQUEST_UPDATED,
codebuild.EventAction.PULL_REQUEST_REOPENED,
).and_base_ref_is(f"^refs/heads/{branch_source2}.*$"),
],
identifier="source2",
)
...
app_project = codebuild.Project(
self,
"codebuild-app",
source=source1,
secondary_sources=[source2],
badge=True,
build_spec=build_spec_source1,
description=f"Builds target images from {branch_source2} branch.",
environment=common_build_env,
logging=logging_app,
project_name=f"builds-app-{branch_source2}",
)

```

### Possible Solution

Not sure but the source declared as the primary source works well, so not sure why that's not happening for the ones in the secondary sources array.

### Additional Information/Context

_No response_

### CDK CLI Version

2.99.1 (build b2a895e)

### Framework Version

2.95.1

### Node.js Version

v20.6.0

### OS

Debian slim bookworm (12.0)

### Language

Python

### Language Version

3.11

### Other information

_No response_

Start by tracing the codebuild.Source.git_hub() and Project secondary_sources handling, then compare how webhook configuration is applied to the primary and secondary sources. Reproduce the example with two GitHub sources and verify that updates to either source register the expected webhook and trigger a build.

Written by the indexing model from the issue text.