chore: Update ghcr.io/grafana/grafana-build-tools Docker tag to v1.47.0

| datasource | package                             | from    | to      |
| ---------- | ----------------------------------- | ------- | ------- |
| docker     | ghcr.io/grafana/grafana-build-tools | v1.46.0 | v1.47.0 |


Signed-off-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>
Signed-off-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>

Author: renovate-sh-app[bot]

.gbt.mk

@@ -4,4 +4,4 @@
 # and a shell script. This is achieved by using the `VAR=value` syntax, which
 # is valid in both Makefile and shell.
 
-GBT_IMAGE=ghcr.io/grafana/grafana-build-tools:v1.46.0@sha256:295103f9021a79d414e72f1de0e1258a00379399841b5dac4dd38fb4462ac40c
+GBT_IMAGE=ghcr.io/grafana/grafana-build-tools:v1.47.0@sha256:a80098070f2bb1b3c8b74160803c97955c66038a925e8814b91ebbe63f1fd36c