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

The bug

When a /tag 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. Place three armor stands

2. /tag @e[type=armor_stand] add test

3. Place one more

4. /tag @e[type=armor_stand] add test

Expected result

Should say “Added tag ‘test’ to Armor Stand”

Observed result

Says “Added tag ‘test’ to 4 entities”

Notes

/tag add and /tag remove 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