bitmap.blit type checking and raise error

[FoamyGuy]

resolves #5916 I confirmed the hard crash as described in the issue.

Tested on Feather TFT ESP32-S2 using this example code (mostly the same as posted in the issue):

import time
import displayio

print("waiting 8...7...6..5...4...3...2...1...")
time.sleep(8)

with open("/allblue.bmp", "rb") as bits:
    source = displayio.OnDiskBitmap(bits)
    dest = displayio.Bitmap(source.width, source.height, 64)
    dest.blit(0, 0, source)

output after this change:

code.py output:
waiting 8...7...6..5...4...3...2...1...
Traceback (most recent call last):
  File "code.py", line 12, in <module>
TypeError: source_bitmap must be of type Bitmap

[jepler]

Thank you, this is just what I expected to see.

[kmatch98]

I tested on the PyPortal.

Interestingly, before the change it didn't crash, but I don't think it actually "blitted" anything.

After the change, I get this exception:

code.py output:
Traceback (most recent call last):
  File "code.py", line 10, in <module>
TypeError: source_bitmap must be of type Bitmap

Code done running.

Looks good to me.