* Revert "feat(base/ui/native): Convert rem to px  (#15934)"

This reverts commit 057dc0e4d2.

* Revert "fix(StageParticipantNameLabel): size"

This reverts commit a01f4468a0.

* Revert "fix(subtitles): position part1"

This reverts commit 6c6ed8d7a8.

* Revert "fix(ITypographyType): wrong type of fontSize and lineHeight props"

This reverts commit bffcc9092b.

* revert(Tokens): font sizes and line heights back to px from rem

Turns out there are many places that does not expect rem. Temporary reverting this change from commit 6fa94b0bb4. We should bring it back along with proper handling of rem everywhere.

There are still many places where theme.spacing is expected to be number. Reverting parts of 057dc0e4d2 .

Fixes an issue where subtitles are displayed in the middle of the screen. This is caused because the bottom prop is calculated to an invalid (NaN) value after we started using rem instead of px for lineHeight in theme.
Reference: https://github.com/jitsi/jitsi-meet/pull/15917

* feat(base/ui): create and use conversion helpers for tokens on mobile

* Make createColorTokens generate values based on jitsiTokens and tokens

Bring web and native more in line