The success message of `/effect` reports that it affected more entities than it did

The bug

When an /effect command targets multiple entities, it can succeed for some but fail for others. In this case, the command’s result correctly returns the number of entities that were affected, but the feedback message incorrectly shows the number of entities that were targeted.

How to reproduce

1. Drop three items on the ground in front of you

2. /effect give @e[distance=..5] speed

Expected result

Should say “Applied effect Speed to (your name)”

Observed result

Says “Applied effect Speed to 4 targets”

Notes

/effect give and /effect clear are both affected. If execute store is used, the result is properly 1, not 4. If no entities are affected, the command properly fails.

This issue was split from MC-122717