Alcohol level still the same after being soaked with dried fruit

Assuming that the container you have them in is tightly sealed then the total amount of alcohol in the container will be the same. However, the concentration in the liquid will have changed somewhat, how much depends on how many prunes you put in relative to how much gin.

Basically what happens is that the fruit absorb some of the alcohol and water from the liquid meaning that the gin/liquid has a bit less alcohol in it overall (essentially it is diluted out by the volume of the fruit too). However, I don't know how much of the alcohol would be absorbed by the fruit per volume.

I wouldn't expect the alcohol level to change much, but it will change some. Gin and other liquors are actually mostly water, or at least a significant percentage will be water. Typically gin is somewhere around 60% water and 40% alcohol, any flavorings are trace elements.

Prunes are dried so they aren't going to contribute moisture to the gin, they will absorb both water and alcohol from the liquor. The question is whether the prunes will absorb more alcohol or more water, or both equally. I have no scientific basis to answer that, so I'll apply some rough numbers to show what the possibilities are.

Say alcohol is absorbed 30% more than water in the fruit, which is a guess but about the maximum difference I'd expect either way. If you have 500ml of gin which is 40% alcohol (80 proof) and the fruit soaks up 100ml of gin then it will absorb about 10ml more alcohol than if it was absorbed evenly. This would reduce the alcohol percentage by around 2.5% of the total volume of the liquor. The opposite works, if the fruit absorbs 30% more water than alcohol the alcohol level would go up 2.5%. These are rough figures, the true figure is dependent on the fruit itself, ratio of fruit to alcohol, alcohol percentage in the liquor, and other factors.