base: Remove unused strings

Change-Id: Icf1a1c50679df64cc1c79e93f20a33212436505e

Conflicts:
	core/res/res/values/cm_strings.xml
core: ES translations

- Transifex export

Change-Id: Ie86f56557f2df45e3832cfdd56ffd2d3e8fbb213

Conflicts:
	packages/SystemUI/res/values-es/cm_strings.xml