fix: errors are not stored for tests

[brainexe]

We noticed two issues after the recent reactoring.

First issue: No errors are stores anymore:

From the log:

Using temp folder /www/ltc/temp/loadtest_1159
Using remote temp folder /tmp/loadtest_1159

-> "errors" were stored in /tmp/loadtest_1159/errors/ But the "analyze_errors" method uses the temp_path aka "/www/ltc/temp/" which does not have logs

Second issue: huge csv files are failing hard to parse:

  File "/www/ltc/ltc/base/models.py", line 929, in parse_csv
    df = df[~df['url'].str.contains('exclude_', na=False)]
  File "/usr/lib/python3/dist-packages/pandas/core/frame.py", line 2688, in __getitem__
    return self._getitem_column(key)
...
KeyError: 'url'