Allow setting ssh or https for repos in fleet

[kwwii]

Fleet should allow for both ssh or https protocols for repos.

Here's a simple mockup of how this should look:

[kwwii]

There was an error in the new drop-down input label - this provides clarity:

The new protocol drop-down should have two values, "ssh://" and "https://". The default selection is https://.

[Josh-Diamond]

Per discussion/decision made here:
#7648 (comment)

This enhancement will consist of a banner being added, stating the following:
Enter a valid HTTPS or SSH URL to a git repository.

This enhancement is NOT expected to add protocol dropdown w/ https or ssh options.

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Ticket #7518 - Test Results - ✅

With Docker on a single-node instance:

Verified on Rancher v2.7-17e5bb595bc7d6d9280dd40280b4e82b21903790-head:

1. Fresh install of Rancher v2.7-head
2. Navigate to Continuous Delivery > GitRepos > Add Repository
3. Verified - Enter a valid HTTPS or SSH URL to a git repository. banner is present and accurate

Screenshot: