The "Debug Shaders" dialog icon was missing when a translation was used.

This commit fixes #3998.
Add a Galician translation.

The composition of the translation team can be found on Transifex: https://www.transifex.com/projects/p/mpc-hc/language/gl/members/.
Add a Vietnamese translation.

The composition of the translation team can be found on Transifex: https://www.transifex.com/projects/p/mpc-hc/language/vi/members/.