https://bazel.build/external/overview#bzlmod

Bzlmod will be the default in a future Bazel release.
By default it requires projects to be registered with the
Bazel Central Registry (https://registry.bazel.build/) and
thus uses regular releases by default.

Users that want to "live-at-head" can still do this through
with overrides (https://bazel.build/external/module#overrides).

This change updates Abseil dependencies to use released versions.
CI uses Bzlmod except in the case of linux_gcc-floor, which will
keep testing the old WORKSPACE-based dependency system.

PiperOrigin-RevId: 597676666
Change-Id: I8d33facc432477c6dc7daa06fd00bb4ae8c4adba