[ticket/12950] Force the installer to use language=en

PHPBB3-12950
Merge remote-tracking branch 'github-dhruvgoel92/ticket/12950' into develop-ascraeus

* github-dhruvgoel92/ticket/12950:
  [ticket/12950] Force the installer to use language=en
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/12950] Force the installer to use language=en