When having two objects selected that use the same action,
the Graph Editor would effectively show the same FCurve on 2 channels.
When building the `TransData` array the code would iterate
all channels though not checking for duplicate FCurves.
As a result when transforming keys, the `TransData`
array would contain the same entry twice.
That would break the logic introduced in c6c7d3d8c4 which
builds a Map of the `float *` that needs
updating and the index of that data in the array.
Only the first index of the `TransData` array would be updated since the
Map can only contain a certain value once.
The fix is to ensure that entries in the `TransData` array are unique.
This is done in the construction of the array.
Pull Request: https://projects.blender.org/blender/blender/pulls/127911
6ea0b8cdb2