[stable2.2] fix(imap): Chunk MessageMapper::findByIds by command length

[backportbot-nextcloud]

• ⚠️ This backport had conflicts that were resolved with the 'ours' merge strategy and is likely incomplete

backport of #8383

[ChristophWurst]

@GretaD you don't have to update a branch when it's outdated fyi

I only enabled the Github feature to make it easier to update branches when really necessary

[GretaD]

@GretaD you don't have to update a branch when it's outdated fyi

I only enabled the Github feature to make it easier to update branches when really necessary

ah, ok, how can i tell that is really necessary?

[ChristophWurst]

when it conflicts or there are changes on the base branch that are needed to make the feature work or CI pass