In the Track List, place the mouse pointer at the very bottom left of the track header. You will see a 'single finger' mouse pointer. This allows you to individually resize tracks. A SHIFT click will reset all tracks to the same height.
A good general way to find out if Logic can do something is to type a word or two into the search field of the KeyCommands window. Logic has the most amount of assignable keycommands that I've ever seen in any program.
I just did a search for "track zoom" and found a function called "individual track zoom reset for all tracks". It does what you need.