[db] Fix collation drift with old installations

[geropl]

Description

Fixes an issue where in very old installations we have a case of COLLATION drift in two tables.

This PR fixes the issue by:

1. explicitly setting the default COLLATION (depending on MySQL version)
2. CONVERT ... COLLATE (depending on MySQL version)

We did extensive testing on a) data consistency and b) runtime impact of the migrations which is negligible (<8s). ✔️

Related Issue(s)

Fixes CLC-1303
Fixes CLC-1439

How to test

1. see here for the test protocol, and verify it invalidates all concerns ✔️
2. smoke test:

• start a workspace in the preview
• once running, visit /org-admin and notice the workspaces list at the bottom shows your workspace ✔️

3. CI tests are 🟢 : ✔️

Documentation

Preview status

gitpod:summary

Build Options

Build

• /werft with-werft
  Run the build with werft instead of GHA
• leeway-no-cache
• /werft no-test
  Run Leeway with --dont-test

Publish

• /werft publish-to-npm
• /werft publish-to-jb-marketplace

Installer

• analytics=segment
• with-dedicated-emulation
• workspace-feature-flags
  Add desired feature flags to the end of the line above, space separated

Preview Environment / Integration Tests

• /werft with-local-preview
  If enabled this will build install/preview
• /werft with-preview
• /werft with-large-vm
• /werft with-gce-vm
  If enabled this will create the environment on GCE infra
• /werft preemptible
  Saves cost. Untick this only if you're really sure you need a non-preemtible machine.
• with-integration-tests=all
  Valid options are all, workspace, webapp, ide, jetbrains, vscode, ssh. If enabled, with-preview and with-large-vm will be enabled.
• with-monitoring

/hold

[geropl]

Let's merge this on Monday 🤝

[kylos101]

✅ per https://gitpod.slack.com/archives/C071G5TTS49/p1750425090675969?thread_ts=1750413005.820499&cid=C071G5TTS49