## Description
This PR ensures that activity-based deadline extensions ("activity
bumping") are not applied to prebuilt workspaces. Prebuilds are managed
by the reconciliation loop and must not have `deadline` or
`max_deadline` values set or extended, as they are not part of the
regular lifecycle executor path.
## Changes
- Update `ActivityBumpWorkspace` SQL query to discard prebuilt
workspaces
- Update application layer to avoid calling activity bump logic on
prebuilt workspaces
Related with:
* Issue: https://github.com/coder/coder/issues/18898
* PR: https://github.com/coder/coder/pull/19252
Susana Ferreira
560cf84251