is THIS is the light in question?
drilling a hole in the lens would provide drainage and might help with moisture inside the lens/around the bulb socket.
have you taken off the light and looked at all the parts?
if so, a PHOTO or 2 here
might help folks to provide better ideas.
is the black base/lens ONE UNIT like the newer led running lights?
with NO replaceable parts INSIDE/under the lens? with the lens GLUED to the base?
IF the issue is the gasket UNDER the light base, against the interstate shell/surface...
one could REMOVED light, DRY the gasket completely, reinstall and then...
add a urethane sealant round the perimeter (white, black or silver)...
this would keep water way from the gasket providing the sealant is intact.
otoh, if the LENS is removable to service the bulb, the small weep hole is probably a good idea.
applying sealant may not LOOK pretty but if the gap is small enough (1-2mm) to use acryl-r...
this stuff really looks good when dry, even in the hands of us amateurs.
sorta like a silver pinstripe around the edges.
adding a thin bead of sealant isn't a guarantee that water won't happen,
as the pics in post #7 clearly show both (sealant and water)...