Error building COLR v0 OTF font

The changes in #610 assume that the font has a "glyf" table, which OTF fonts do not.

```
gftools builder sources/config.yaml

[...]

[42/60] fix
FAILED: ../fonts/otf/MyFont-ExtraBold.otf
/home/user/myfont/.venv/bin/python3 -m gftools.builder.jobrunner gftools-fix-font -o ../fonts/otf/MyFont-ExtraBold.otf /tmp/tmpf2k52f6_

Command failed:
gftools-fix-font -o ../fonts/otf/MyFont-ExtraBold.otf /tmp/tmpf2k52f6_

INFO:gftools.fix:Updated license strings
INFO:gftools.fix:Added GASP and prep tables for unhinted font
Traceback (most recent call last):
File "/home/user/myfont/.venv/bin/gftools-fix-font", line 8, in
sys.exit(main())
File "/home/user/myfont/.venv/lib/python3.10/site-packages/gftools/scripts/fix_font.py", line 50, in main
font = fix_font(font, args.include_source_fixes, args.rename_family, axis_dflts)
File "/home/user/myfont/.venv/lib/python3.10/site-packages/gftools/fix.py", line 914, in fix_font
result = fixer(fixed_font)
File "/home/user/myfont/.venv/lib/python3.10/site-packages/gftools/fix.py", line 808, in fix_colr_font
return fix_colr_v0_gid1(ttfont)
File "/home/user/myfont/.venv/lib/python3.10/site-packages/gftools/fix.py", line 702, in fix_colr_v0_gid1
glyf_table = ttfont["glyf"]
File "/home/user/myfont/.venv/lib/python3.10/site-packages/fontTools/ttLib/ttFont.py", line 455, in __getitem__
table = self._readTable(tag)
File "/home/user/myfont/.venv/lib/python3.10/site-packages/fontTools/ttLib/ttFont.py", line 462, in _readTable
data = self.reader[tag]
File "/home/user/myfont/.venv/lib/python3.10/site-packages/fontTools/ttLib/sfnt.py", line 108, in __getitem__
entry = self.tables[Tag(tag)]
KeyError: 'glyf'
```