Fix deletion of multiple features

[gabriel-bolbotina]

Fixed issue when deleting multiple features for the second time, as described in this comment:
#4097 (comment)

fixes #4097

[Withalion]

let's wait for builds to finish until merging, and also probably for @IvaKuklica approval

[github-actions]

Pull Request Test Coverage Report for Build 19892288606

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 28 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.1%) to 59.586%

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Files with Coverage Reduction	New Missed Lines	%
mm/app/multieditmanager.cpp	6	50.4%
mm/core/merginuserauth.cpp	9	68.24%
mm/core/merginapi.cpp	13	75.15%

Totals
Change from base Build 19892247371:	-0.1%
Covered Lines:	8544
Relevant Lines:	14339

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💛 - Coveralls