fix!: correct pixel origin string to upper left instead of lower left

Description

The pixel origin lower left is actually upper left. Luckily all logic is correct, just the naming wrong.

I didn't create any deprecation as this is a serious misnomer a user should be informed about the change. All dataset definitions are updated in this PR, so in case of the public datasets nothing has to be changed. In case of local datasets the user will be notified to change the experiment definition to upper left this way.

I think this is the best solution, as adding the correct calculation for lower left (and potentially others) would result in silent errors for users which created dataset definitions with pymovements<v0.18.0. This way we have at least a few versions inbetween that notify the user of this bugfix.

Implemented changes

[x] replace the string "lower left" with "upper left" in all files
[x] add helpful error message to update dataset definition

Type of change

[x] Bug fix (non-breaking change which fixes an issue)
[x] Breaking change (fix or feature that would cause existing functionality to not work as expected)

How Has This Been Tested?

[x] test helpful error message

Checklist:

[x] My code follows the style guidelines of this project
[x] I have performed a self-review of my own code
[x] I have commented my code, particularly in hard-to-understand areas
[x] I have made corresponding changes to the documentation
[x] My changes generate no new warnings
[x] I have added tests that prove my fix is effective or that my feature works
[x] New and existing unit tests pass locally with my changes
[x] Any dependent changes have been merged and published in downstream modules
[x] I have checked my code and corrected any misspellings

aeye-lab / pymovements