[CommCoreModule] add StoreOperationsBase virtual destructors

Summary:
I added ThreadStoreOperationsBase and MessageStoreOperationsBase virtual destructors to avoid warnings during app build on Android. The change doesn't affect app behavior.
Notion task: https://www.notion.so/commapp/ThreadStore-C-warning-18ae0a3a7ae243cab23aee79edf9b8f1

Test Plan: I build the app succesfully on iOS and Android. The warning doesn't appear.

Reviewers: palys-swm, ashoat, atul

Reviewed By: ashoat

Subscribers: ashoat, palys-swm, Adrian, atul, karol-bisztyga, benschac, boristopalov

Differential Revision: https://phabricator.ashoat.com/D2268