WIP: ensure nightly builds always produce new packages

[jameslamb]

Contributes to rapidsai/build-planning#218

• uses the new patterns for versioning nightly packages (see builds: add support for computing a date-based version component at build time shared-workflows#603), to ensure they're always uploaded on new builds.

For wheels:

# before
26.10.0a55 

# after
26.10.0a55.post260803200854

And for conda:

# before
26.10.0a55[build=cuda12_260803_9da146ef]

# after
26.10.0a55[build=cuda12_260803200854_9da146ef]

Other changes:

• updates the check-nightly-conda-env code to handle these more-precise date-time components in conda build strings

Notes for Reviewers

How I tested this

See rapidsai/cugraph-gnn#508

[copy-pr-bot]

Auto-sync is disabled for draft pull requests in this repository. Workflows must be run manually.

Contributors can view more details about this message here.

[jameslamb]

Proposing doing this in the same PR to also test that all RAPIDS packages have appropriately-updated version components.

That'll mean this is the last PR in the series to merge, I think that's totally fine.

[jameslamb]

/ok to test