Allow testing frontend branches on gitpod

it seems we already have a FRONTEND_BRANCH variable, but it was not fully working yet. So fixed it. https://github.com/drunomics/lupus-decoupled-project/pull/13/files

Test-Link
https://gitpod.io/new/#DP_PROJECT_NAME=lupus_decoupled,DP_ISSUE_BRANCH=1.x,DP_PROJECT_TYPE=project_module,DP_MODULE_VERSION=1.x,DP_CORE_VERSION=10.3,DP_PATCH_FILE=,FRONTEND_REPOSITORY=https%3A%2F%2Fgithub.com%2Fdrunomics%2Flupus-decoupled-nuxt3-demo,FRONTEND_BRANCH=feature%2FLDP-2606,CUSTOM_ELEMENTS_VERSION=3.*,DP_INSTALL_PROFILE=standard/https://github.com/drunomics/lupus-decoupled-project/tree/feature/frontend-branch

works!

Automatically closed - issue fixed for 2 weeks with no activity.