Traceback with AlignmentZones custom parameter

I have a .glyphs file where each master has an alignmentZones custom parameter, like this:
```
alignmentZones = (
"{671, 12}",
"{612, 18}",
"{574, 12}",
"{495, 16}",
"{465, 14}",
"{436, 14}",
"{416, 18}",
"{0, -18}",
"{-211, -18}"
);
```

This results in the following traceback:
```
Traceback (most recent call last):
File "glyphs2ufo", line 8, in
sys.exit(_glyphs2ufo_entry_point())
File "python3.10/site-packages/glyphsLib/cli.py", line 276, in _glyphs2ufo_entry_point
return main(args)
File "python3.10/site-packages/glyphsLib/cli.py", line 234, in main
return options.func(options)
File "python3.10/site-packages/glyphsLib/cli.py", line 253, in glyphs2ufo
glyphsLib.build_masters(
File "python3.10/site-packages/glyphsLib/__init__.py", line 155, in build_masters
source.font.save(ufo_path)
File "python3.10/site-packages/ufoLib2/objects/font.py", line 593, in save
self.write(writer, saveAs=saveAs)
File "python3.10/site-packages/ufoLib2/objects/font.py", line 520, in write
writer.writeInfo(self.info)
File "python3.10/site-packages/fontTools/ufoLib/__init__.py", line 1301, in writeInfo
infoData = validateInfoVersion3Data(infoData)
File "python3.10/site-packages/fontTools/ufoLib/__init__.py", line 1867, in validateInfoVersion3Data
raise UFOLibError(f"Invalid value for attribute {attr} ({value!r}).")
fontTools.ufoLib.errors.UFOLibError: Invalid value for attribute postscriptBlueValues ([-18, 0, 416, 434, 436, 450, 465, 479, 495, 511, 574, 586, 612, 630, 671, 683]).
```

The problem here is that that’s just too many zones. ufoLib’s `fontInfoPostscriptBluesValidator` rejects the list of values because more than 7 pairs are supplied, which is not allowed per the CFF spec: https://github.com/fonttools/fonttools/blob/main/Lib/fontTools/ufoLib/validators.py#L305-L306

This problem could be fixed by editing `to_ufo_blue_values ` in `blue_values.py`:

```py
def to_ufo_blue_values(self, ufo, master):
"""Set postscript blue values from Glyphs alignment zones."""

alignment_zones = master.alignmentZones
blue_values = []
other_blues = []
for zone_index, zone in enumerate(sorted(alignment_zones)):
pos = zone.position
size = zone.size
val_list = blue_values if pos == 0 or size >= 0 else other_blues
if zone_index <= 7:
val_list.extend(sorted((pos, pos + size)))
else:
logger.warning(f'Surplus alignment zone {pos}, {pos + size} omitted')

if blue_values:
ufo.info.postscriptBlueValues = blue_values
if other_blues:
ufo.info.postscriptOtherBlues = other_blues

```

Start in blue_values.py at to_ufo_blue_values and reproduce the glyphs2ufo conversion with a .glyphs file containing the shown alignmentZones. Check how surplus zones are handled and confirm the resulting UFO saves without the postscriptBlueValues validation traceback, with a warning for omitted zones.

Written by the indexing model from the issue text.