Fix compilation & API docs build error

[rajat2004]

Sphinx gives the following error -

WARNING: autodoc: failed to import module 'utils' from module 'airsim'; the following exception was raised:
Traceback (most recent call last):
  File "/home/rajat/.py-envs/airsim/lib/python3.6/site-packages/sphinx/ext/autodoc/importer.py", line 66, in import_module
    return importlib.import_module(modname)
  File "/usr/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/home/rajat/AirSim/PythonClient/airsim/__init__.py", line 1, in <module>
    from .client import *
  File "/home/rajat/AirSim/PythonClient/airsim/client.py", line 270
    return self.client.call('simRunConsoleCommand', command)
                                                           ^
TabError: inconsistent use of tabs and spaces in indentation

And the second one fixes the compilation caught in CI, introduced by #2841

 C:/__w/14/s/Unreal/Environments/Blocks/Plugins/AirSim/Source/SimHUD/SimHUD.cpp(340): error C4456: declaration of 'vehicle_sim_api' hides previous local declaration
  C:/__w/14/s/Unreal/Environments/Blocks/Plugins/AirSim/Source/SimHUD/SimHUD.cpp(322): note: see declaration of 'vehicle_sim_api'