[web] fix docker image tag for branch builds (#29109)

GitOrigin-RevId: 07e9b6a615622a0d6b9dbc2fbc43434752cc2a9b

services/web/Makefile

@@ -546,7 +546,7 @@ shellcheck_fix:
 
 IMAGE_CI ?= ci/$(PROJECT_NAME):$(BRANCH_NAME)-$(BUILD_NUMBER)
 IMAGE_REPO ?= us-east1-docker.pkg.dev/overleaf-ops/ol-docker/$(PROJECT_NAME)
-IMAGE_REPO_FINAL ?= $(IMAGE_REPO):main-$(BUILD_NUMBER)
+IMAGE_REPO_FINAL ?= $(IMAGE_REPO):$(BRANCH_NAME)-$(BUILD_NUMBER)
 IMAGE_CACHE ?= $(IMAGE_REPO):cache-$(shell cat \
 	$(MONOREPO)/package.json \
 	$(MONOREPO)/package-lock.json \