Bump blockly from 11.2.2 to 12.5.1 in /src-editor

Bumps [blockly](https://github.com/RaspberryPiFoundation/blockly) from 11.2.2 to 12.5.1.
- [Release notes](https://github.com/RaspberryPiFoundation/blockly/releases)
- [Commits](RaspberryPiFoundation/blockly@blockly-v11.2.2...blockly-v12.5.1)

---
updated-dependencies:
- dependency-name: blockly
  dependency-version: 12.5.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]