[BUG] ASE converter crashes randomly.

**Description of the error**
Sometimes, the ASE converter unexpectedly crashes with a `Segmentation fault`.

Recently, this has been observed on MacOS (ARM) with ASE version `3.25.0`. The same/similar problem has been reported before in #592

**Describe the expected result**
The trajectory conversion should complete uninterrupted.

**Describe the actual result**
The conversion job crashes with a segmentation fault (no Python traceback), destroying the GUI.

**Suggested fix**
To some extent this may be a problem on the ASE end. Would it help to change the way ASE converter iterates over frames?

**Additional details**
N/A

Start by reproducing the ASE converter crash on macOS ARM with ASE 3.25.0, then review the related report in issue #592 and the converter's frame-iteration entry point. Done means trajectory conversion completes uninterrupted without a segmentation fault or GUI crash.

Written by the indexing model from the issue text.