Custom Study: New Card Increases by Wrong Number

## Steps

1. Finish your new cards for the day.
2. Go to deck options and reduce the new card limit.
3. Use custom study to increase new card limit.

## Behaviour

Say, if you decrease the preset limit by 2 and then use custom study to increase new card limit by 5, in this case you'll introduce only 3 new cards and not the expected 5.

*Originally posted by @brishtibheja in https://github.com/ankidroid/Anki-Android/issues/17697*

Reproduce the problem through deck options and Custom Study using the stated limit changes, then trace the code handling the new-card limit increase. Done means increasing the limit by 5 introduces 5 new cards even after the preset limit was reduced by 2.

Written by the indexing model from the issue text.