The titanium Birdy has disc brakes only (no mountings for any type of rim brakes), so changing the wheel size causes no problems for the brakes.

Most people who change their wheels for another size have disc brake Birdy.

Now the position difference of the bake shoes for ETRTO 349 vs. ETRTO 355 is only 3mm down, you should be able to test if you can lower the shoes by 3mm before changing the wheels.

Just for remembrance, Brompton wheels won't fit on the Birdy since the OLD front and rear are different.