Time series data load from csv stalls if timestamps have timezone information appended

**Describe the bug**
I have two separate csv files used to create "activity recognition tasks". Literally the only difference between the two is the format of the timestamps. File 1 was generated directly from time series data stored in a `pandas.DataFrame` object, using a `pandas.DatetimeIndex` for the index. It was then exported using `pandas.DataFrame.to_csv(..., index=True)`. This will generate datetime-aware timestamps in the following format: `YYYY-MM-DD hh:mm:ss.f+00:00` which looks like `2024-04-11 12:25:59.487929+00:00`. File 2 is the same file, but with the timezone information scrubbed from the datetime (e.g. `YYYY-MM-DD hh:mm:ss.f` which looks like `2024-04-11 12:25:59.487929`.

When file 1 is loaded, the data will not load and a spinner shows indefinitely:

The console logs several errors that are not particularly useful/diagnostic and may not even be related, mostly various "cannot read properties of undefined" errors, which leads me to think this could be masking issues identified in other bug reports [like this one](https://github.com/HumanSignal/label-studio/issues/3094). Kudos to [this comment](https://github.com/HumanSignal/label-studio/issues/3094#issuecomment-1759592717) which pointed me to this issue in the first place.

File 2 loads normally, so the format is obviously the culprit.

**To Reproduce**
1. Create a simple time series csv file with the following format for datetimes in the first column: `YYYY-MM-DD hh:mm:ss.f+00:00` which looks like `2024-04-11 12:25:59.487929+00:00`
2. Save a copy of this file, but with the timezone info removed from the datetimes. They should be in the format: `YYYY-MM-DD hh:mm:ss.f` which looks like `2024-04-11 12:25:59.487929`.
3. Generate tasks for both of these time series.
4. Set up a time series activity recognition or similar annotation template.
5. Try to annotate file 1 and observe spinner.
6. Try to annotate file 2 and see data load. Load data, load.

**Expected behavior**
Data loads into template in step 5 as well.
OR
* Documentation is exceedingly clear about accepted time series formats. E.g. "only use POSIX timestamps in UTC" or something of that nature.
* If a time series is loaded and does not match one of the accepted datetime formats, the user receives a nudge on the frontend to correct it.

**Environment (please complete the following information):**
- Chrome 130.0.6723.70 on Macos 14.6.1 (Sonoma)
- AWS EKS deployment from latest Helm chart
- Label Studio 1.13.1