luci-base: Hardcode 'openwrt-24.10' as the branch name

luci-base: Hardcode 'openwrt-24.10' as the branch name

Hardcode 'openwrt-24.10' release branch as the branch name to avoid
'LuCI (HEAD detached at 2ac26e56) branch' being shown as the branch.

Feeds are since March 2025 cloned shallow if cloned from a specific
commit, like done with a release tag. Change in OpenWrt:
https://github.com/openwrt/openwrt/commit/32d0a57dc10811a24816e51f10e55963f40fe462

As the only cloned commit of a release tag is without history, the branch
can't be identified.

So, hardcode the branch name to get the proper branch name
'LuCI openwrt-24.10 branch'.

Fixes #7737

Signed-off-by: Hannu Nyman <[email protected]>