[40/44] Enable TS strict mode in dotcms-block-editor

Description

Part of the strict-mode rollout epic #35932. Enable TypeScript strict mode for the dotcms-block-editor app.

• Dependency layer: 7
• Rollout order: 40 / 44

Acceptance Criteria

• The six strict flags are added to apps/dotcms-block-editor/tsconfig.json.
• tsc -p reports 0 errors on all three configs — tsconfig.app.json, tsconfig.spec.json and tsconfig.editor.json.
• nx run dotcms-block-editor:build passes. This app has a build target, so unlike most projects in this epic it is genuinely CI-enforced — and a build checks templates, which tsc -p does not.
• nx run dotcms-block-editor:lint introduces no new findings.

[!IMPORTANT]
typescript-strict-plugin / npx tsc-strict / @ts-strict-ignore are not used. See core-web/CLAUDE.md → TypeScript Strict Mode. The original ACs have been corrected.

The measurement was masked before any of this

Three of this app's tsconfigs declared "types": ["jasmine", "node"]. @types/jasmine is not installed — nor are karma-jasmine or jasmine-core — so each aborted with TS2688 before semantic checking. None of them had ever type-checked anything.

The test target is @angular/build:karma with a karma.conf.js, but with none of the Karma packages installed it cannot run, and the app has no .spec.ts files at all. "types": ["node"] is the truthful set.

Priority

Medium

Start with apps/dotcms-block-editor/tsconfig.json and its tsconfig.app.json, tsconfig.spec.json, and tsconfig.editor.json files. Run tsc -p for all three configs, then nx run dotcms-block-editor:build and nx run dotcms-block-editor:lint. Done means the six strict flags are enabled, all checks pass, and no new lint findings appear.