Update git submodules
- Update extensions/FlaggedRevs from branch 'wmf/1.38.0-wmf.9' to rEFLR25ffc46d494f
- Do not inject rev id of template when it's empty
It doesn't serve any purpose
Change-Id: I2c43b9ee903fb44fadd12ebae54a9bfc2f207e40 (cherry picked from commit 03b206384c00e2001dc71605aeebcd9e38b8c8fa)
- Do not inject rev id of template when it's empty