Revert " Email: Allow theming via theme chooser"

This reverts commit 6f203142be66ca46f4c5e6efa7c631c4d668d07f.
TRDS:[UnifiedEmail] Dark Email (2/2)

Change-Id: Ib3b760fc4cb6bb346cb7e42bea856a238f065557
trds: color adjustments

Change-Id: Ifbb8853309c7a08958da5d89df252baf7ce1b0ee
trds: fix white bg on email compose for sw600dp

Fix it fix it :)

Change-Id: Ib10715deacdcab6fbc779558bb03e7edd45a71c4