Temporarily revert fix for SpatialSeries.bounds

[rly]

Motivation

Fix #1992

Checklist

• Did you update CHANGELOG.md with your changes?
• Have you checked our Contributing document?
• Have you ensured the PR clearly describes the problem and the solution?
• Is your contribution compliant with our coding style? This can be checked running ruff check . && codespell from the source directory.
• Have you checked to ensure that there aren't other open Pull Requests for the same change?
• Have you included the relevant issue number using "Fix #XXX" notation where XXX is the issue number? By including "Fix #XXX" you allow GitHub to close issue #XXX when the PR is merged.

[rly]

Because we reverted commits in nwb-schema, the order of adding pynwb support for changes in nwb-schema 2.8.0 is no longer straightforward (and may not even be possible to not have issues). I will merge this and the other schema 2.8.0 PyNWB PRs into the nwb_schema_2.8.0 branch and look at what issues, if any, remain.