fixing invalid literal for int() with base 10 error in cli.py

[dkazanc]

Fixes:

Traceback (most recent call last):
  File "/dls_sw/apps/httomo/latest/build/httomo/cli.py", line 355, in transform_limit_str_to_bytes
    return int(limit_str)
           ^^^^^^^^^^^^^^
ValueError: invalid literal for int() with base 10: '44038400000.0'

Checklist

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have made corresponding changes to the documentation
• I have added the user-release-note label in order to include this PR in the "Notable
  Changes for Users" section in release notes