tweak asking for "disable battery optimisations"

[r10s]

do not ask for "disable battery optimisations" when all accounts are chatmail and we got a push token.

with chatmail, we reduced the number of questions from three to only one (or zero for android<=12):

if classic mail is used, the following questions follow - either for the first account, but also anytime later when a non-chatmail is added:

the push token, however, is got unconditionally from the other states - it is a cheap call, the device is connected to the PUSH server anyways and we want to leave it up to core what to do with it

[github-actions[bot]]

To test the changes in this pull request, install this apk: 📦 app-preview.apk

[github-actions[bot]]

To test the changes in this pull request, install this apk: 📦 app-preview.apk