Add new strings for Wi-Fi hotspot toggle specific scenario

- The SW (Swahili) language is used for a different noun class and is
inappropriate in the context.

- Need to separate different strings for specific situations.

- Add new strings to SettingsLib to share multiple packages (e.g.
Settings, Quick Settings)

Bug: 168801172
Bug: 168733667
Test: Manual test
Change-Id: I6728064f6743d89418cdf7ed1c4c2ade797a3d7d