`zig fetch` does not resolve `git+https` ref to commit hash when overwriting existing dependency

[castholm]

Zig Version

0.14.0-dev.1710+8ee52f99c

Steps to Reproduce and Observed Behavior

1. Run zig init in an empty directory.
2. Run zig fetch --save=glfw https://pkg.machengine.org/glfw/e6f377baed70a7bef9fa08d808f40b64c5136bf6.tar.gz (the actual tarball is irrelevant, I used slimsag/glfw as an example as this was where I encountered the issue).
3. Open build.zig.zon and observe that the dependency glfw has been added with the URL from step 2.
4. Run zig fetch --save=glfw git+https://github.com/slimsag/glfw (as with above, the actual repo is irrelevant as long as it's a git repository).
5. Open build.zig.zon and note that the url was changed to git+https://github.com/slimsag/glfw, without a commit hash fragment.

If you delete the glfw entry and run zig fetch --save=glfw git+https://github.com/slimsag/glfw anew, its url is resolved to the expected git+https://github.com/slimsag/glfw#e6f377baed70a7bef9fa08d808f40b64c5136bf6 with the commit hash fragment.

Expected Behavior

Overwriting the existing dependency im step 4 resolves the ref to a commit hash as expected.