Remove trailing slash in targetBaseEndpoint for vcs agent config

[tomasmik]

Description of the change

Remove the trailing slash from the targetBaseEndpoint

Type of change

• Bug fix (non-breaking change that fixes an issue);
• New feature (non-breaking change that adds functionality);
• Breaking change (fix or feature that would cause existing functionality not to work as expected);
• Other (miscellaneous, GitHub workflow changes, changes to the PR template);

Checklists

Development

• Lint rules pass locally;
• All tests related to the changed code pass in development;

Code review

• This pull request has a descriptive title and sufficient context for a reviewer. There may be a screenshot or screencast attached;
• This pull request is no longer a draft;

Deployment

• Selected merge strategy is squash merge;
• Changes have been reviewed by at least one other engineer;

[adamconnelly]

One other thought - we could use url.Parse to ensure it's a valid URL, and also make sure it's in the correct format that we need. But I'm happy with just trimming the end of the string, so no worries if you don't think that makes sense.