Add error message for invalid event data names

[s3n-w6i]

During my profiling, I added an event to preCICE that wrote custom data named rank. When I went to run precice-profiling-export on it, I received the following error:

polars.exceptions.ShapeError: 13 column names provided for a DataFrame of width 12

After some digging, it turns out that this mismatch in columns is due to a collision between the rank field that is included by default in the exported CSV file and the rank I added as custom event data.

I added an assertion that catches this duplicate and prints a custom error message, so that the user knows what's going on:

AssertionError: Event data must not be named 'rank', because it collides with a built-in name

Alternatives considered

• be able to use built-in names and instead:
  • prefix event data columns with something like "data_" (breaking)
  • or have duplicate names in the exported CSV files. Does not seem straightforward to implement, since we go through polars and polars does not allow for duplicated column names. Also, a consumer of the CSV file will likely have problems reading it.
• doing nothing: Continue to have a misleading error message