Memory issues even on some Express boards

Re this thread:
https://forums.adafruit.com/viewtopic.php?p=938210

Can recreate via simple REPL import:
```python
Adafruit CircuitPython 7.3.2 on 2022-07-20; Adafruit Feather M0 Express with samd21g18
>>> import adafruit_ht16k33.segments
Traceback (most recent call last):
File "", line 1, in
File "adafruit_ht16k33/segments.py", line 484, in
MemoryError: memory allocation failed, allocating 96 bytes
>>>
```

Reproduce the failure on an Adafruit Feather M0 Express running CircuitPython 7.3.2 by importing adafruit_ht16k33.segments in the REPL. Inspect segments.py around line 484 to determine why the import requires an additional 96-byte allocation. Done means the module imports successfully without MemoryError on the affected board.

Written by the indexing model from the issue text.