[web] fix make test_unit_watch (#33370)

* [web] check for missing module tsconfig in CI

* [web] add missing tsconfig into test_unit container

GitOrigin-RevId: 7b861f8e68f961e3455b72b5660cf3825389c656

services/web/docker-compose.yml

@@ -10,6 +10,7 @@ services:
       - ../../libraries:/overleaf/libraries
       - ../../bin/shared/wait_for_it:/overleaf/bin/shared/wait_for_it
       - ../../tools/migrations:/overleaf/tools/migrations
+      - ../../tsconfig.backend.json:/overleaf/tsconfig.backend.json
       - ../../package.json:/overleaf/package.json
       - ../../.yarnrc.yml:/overleaf/.yarnrc.yml
       - ../../yarn.lock:/overleaf/yarn.lock