Refactoring: Import `example_data_factory()` from tiltIndicator

Relates to https://github.com/2DegreesInvesting/tiltIndicator/pull/776
Relates to #119

This PR deletes the local version of example_data_factory() and instead uses the one directly from tiltIndicator. This ensure the implementation is the same.

TODO

[x] Link related issue/PR.
[x] Describe the goal of the PR. Avoid details that are clear in the diff.
[x] Mark the PR as draft.
[x] Include a unit test.
[x] Review your own PR in "Files changed".
[x] Ensure the PR branch is updated.
[ ] Ensure the checks pass.
[ ] Change the status from draft to ready.
[x] Polish the PR title and description.
[ ] Assign a reviewer.

EXCEPTIONS

[ ] Slide here any item that you intentionally choose to not do.

2DegreesInvesting / tiltPlot

Refactoring: Import `example_data_factory()` from tiltIndicator #120