Migrate the Settings screen to use DataStore instead of SharedPreferences.

[MohitMaliFtechiz]

Migrate the Settings screen to use DataStore instead of SharedPreferences.

We have completed the initial setup for DataStore in #4514. Migrating all preferences at once would be large and error-prone, so we are splitting the work into smaller, focused sub-tickets. This ticket covers migrating all preferences used in the Settings screen to DataStore.