support/misc/gitlab-ci.yml.in: check legal-info in run_make

The script "utils/test-pkg" is systematically checking legal-info.
See [1]. This is useful to check all license hashes are up to date.

The Buildroot Gitlab CI integration has an identical testing
capability. It is faster because it can run all supported toolchain
test builds in parallel. See [2].

It was observed in [3] that the Gitlab CI test-pkg variant does not
check legal-info.

This commit align the Gitlab CI test-pkg behavior to the
"utils/test-pkg" script by adding legal-info in the run_make command
targets. Doing so checks legal-info in test-pkg cases, but also in
defconfigs (this was suggested by Arnout in [4]).

[1] https://gitlab.com/buildroot.org/buildroot/-/blob/2025.05/utils/test-pkg#L195
[2] https://gitlab.com/buildroot.org/buildroot/-/blob/2025.05/support/misc/gitlab-ci.yml.in#L129
[3] https://lore.kernel.org/buildroot/75e688887d95948c57a11416de3047b5@free.fr/
[4] https://lore.kernel.org/buildroot/614bec7e-0723-4bbd-8c3a-c801e91c29c3@rnout.be/T/#mcc803eeb38d09c1cc02b1333720845c54af86534

Cc: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>
(cherry picked from commit c84762675c)
Signed-off-by: Titouan Christophe <titouan.christophe@mind.be>

support/misc/gitlab-ci.yml.in

@@ -45,7 +45,7 @@ before_script:
 
 .run_make: &run_make
     |
-      make O=${OUTPUT_DIR} > >(tee build.log |grep '>>>') 2>&1 || {
+      make O=${OUTPUT_DIR} world legal-info > >(tee build.log |grep '>>>') 2>&1 || {
           echo 'Failed build last output'
           tail -200 build.log
           exit 1