test_common.py: Add test_download_ee_image_tiles_parallel

[schwehr]

Test that geemap can call joblib

[jdbcode]

For all of the default arguments can ANY (from unittest.mock import ANY) be used?

[schwehr]

For all of the default arguments can ANY (from unittest.mock import ANY) be used?

I've not had much experience with ANY. I think I'll keep it as is, but if these types of tests are demonstrateably brittle, we should definitely consider it.

[schwehr]

I need to figure out what is up with the docs-build failure:

======================================================================
FAIL: test_download_ee_image_tiles_parallel (test_common.CommonTest.test_download_ee_image_tiles_parallel)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/_temp/uv-python-dir/cpython-3.12.12-linux-x86_64-gnu/lib/python3.12/unittest/mock.py", line 1396, in patched
    return func(*newargs, **newkeywargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/geemap/geemap/tests/test_common.py", line 631, in test_download_ee_image_tiles_parallel
    self.assertEqual(mock_download_ee_image.call_count, 2)
AssertionError: 0 != 2

[schwehr]

I can't figure out why this works locally for me, but not on github.