Allow test.yaml jobs to use the latest branch build if it is more recent than the latest nightly build

[vyasr]

Currently all our test CI jobs use rapids-download-*-from-s3 to get their artifacts (cudf example). These tools all call rapids-download-from-s3, which in turn calls rapids-s3-path. Since rapids-s3-path constructs its path based on the build type, that implicitly means that test.yaml always pulls the build from the corresponding nightly build, even if there was a more recent branch build. This is particularly problematic in light of rapidsai/build-planning#127 since it is now more important to be able to resolve these failures within a given day i.e. by rerunning the test workflow on a branch build. To support this use case, we should make the build type an optional input to the test.yaml workflow to customize which type of build to pull in the workflow. This will allow us to customize running a test workflow on a branch build to unblock CI once fixes are in.

[bdice]

Our build workflows have three options: nightly, pull-request, and branch.

Our test workflows only accept nightly and pull-request as options, so we'd need a third option for branch tests in places like these:

https://github.com/rapidsai/shared-workflows/blob/6b1b82739d30ca3da0335a45722cef8380874241/.github/workflows/conda-cpp-tests.yaml#L53-L58

Then, we should make build_type a configurable input to test.yaml in each repository. The default should be nightly, same as our build workflows, but we need to be able to set build_type: branch in manually triggered runs.

[gforsyth]

I'm targeting the 25.04 for this, but if it would get some 25.02 stuff unblocked I can retarget

[bdice]

I'm targeting the 25.04 for this, but if it would get some 25.02 stuff unblocked I can retarget

25.04 should be fine.

[vyasr]

Agreed it isn't 25.02 urgent.