What I learned overfilling oil.
 

It’s a lesson learned based on my error. I overfilled oil into my engine being just above the full line on my dipstick. It was okay for a week until I had small leaks coming from my engine. Took it to my mechanic and found out that it was coming from one of the oil sensors not knowing how much oil is being pushed out into the engine. So there goes my lesson on putting too much oil into my engine.

Ummmm. I'm not sure what the mechanic told you, but what you wrote here is not a thing.
A little over the fill line should usually be fine, but there are other reasons your car might leak oil that probably deserve attention.

What did the mechanic do to fix this?

How many quarts did you put in when you changed the oil?

The engine doesn’t leak from overfilling. It would more likely puke oil from the pcv system to the intake if it was way overfilled. But back in 2005 I was ignorantly running an extra quart over for autox and it neither leaked nor puked. There was no negative impact at all that I ever detected. Later I learned that wasn’t doing anything beneficial either and then ran the normal level.