Mandate EP size in FP filters when needed

I feel that Footprint filters should included the exposed pad size - there are quite a few TI parts at least where the same filter would match radically different EP sizes.

E.g. RHA:

RHA0040E:

RHA0040(B,C,D) are all different too!

Now that the zone connection is "solid", additional copper area is easy to provide - adding a bigger pad is likely to mean solder paste ends up under non-solderable areas of the IC.

The rule was "Don't include EP size".

Change it to "include it when it is needed to disambiguate footprints"

This means the (many) symbols that use FPs with unambiguous EP sizes won't need revision to avoid new KLC errors.