docker: The cue directory is gone. Catch-up (#52606)

The files got removed in 8876d56495 but
the container was not updated yet.

Dockerfile

@@ -27,7 +27,6 @@ RUN apk add --no-cache gcc g++ make
 WORKDIR /grafana
 
 COPY go.mod go.sum embed.go Makefile build.go package.json ./
-COPY cue cue
 COPY packages/grafana-schema packages/grafana-schema
 COPY public/app/plugins public/app/plugins
 COPY public/api-spec.json public/api-spec.json

Dockerfile.ubuntu

@@ -29,7 +29,6 @@ COPY go.mod go.sum embed.go ./
 COPY Makefile build.go package.json ./
 COPY .bingo .bingo
 COPY pkg pkg/
-COPY cue cue/
 COPY cue.mod cue.mod/
 COPY packages/grafana-schema packages/grafana-schema/
 COPY public/app/plugins public/app/plugins/