The gamerule command succeeds even if no changes are made

This issue relates to MC-271297. The /gamerule command always succeeds, even if the gamerule value remains unchanged. This behavior is observed with both boolean and numeric gamerules.

Steps to reproduce

1. /gamerule keepInventory true

2. /gamerule keepInventory true

3. /gamerule randomTickSpeed 3

4. /gamerule randomTickSpeed 3

Observed result: The commands always succeeded, even if the keepInventory gamerule was already set to true and the randomTickSpeed was already set to 3.
Expected result: If the keepInventory gamerule is already set to true, attempting to set it to true again should produce an error message and cause the command to fail. Similarly, if the randomTickSpeed gamerule is already set to 3, trying to set it to 3 should also produce an error message and cause the command to fail.