[REF-2256] 0.4.5a1: Cannot run --backend-only without a .web directory

[masenf]

Describe the bug
Due to new telemetry routines, Reflex crashes when trying reflex run --backend-only if the project does not have a .web directory.

To Reproduce

reflex init --template blank
rm -rf .web
reflex run --backend-only

Expected behavior
Reflex backend starts normally, with or without the reflex.json file present.

Screenshots

(VENV-pre-0.4.5a) masen@asmbp21 reflex-dev % reflex run --backend-only
───────────────────────────── Starting Reflex App ──────────────────────────────
Traceback (most recent call last):
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/bin/reflex", line 8, in <module>
    sys.exit(cli())
             ^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/typer/main.py", line 328, in __call__
    raise e
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/typer/main.py", line 311, in __call__
    return get_command(self)(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/typer/core.py", line 778, in main
    return _main(
           ^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/typer/core.py", line 216, in _main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/click/core.py", line 1688, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/typer/main.py", line 683, in wrapper
    return callback(**use_params)  # type: ignore
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/reflex/reflex.py", line 262, in run
    _run(env, frontend, backend, frontend_port, backend_port, backend_host, loglevel)
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/reflex/reflex.py", line 215, in _run
    telemetry.send(f"run-{env.value}")
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/reflex/utils/telemetry.py", line 129, in send
    event_data = _prepare_event(event)
                 ^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/reflex/utils/telemetry.py", line 77, in _prepare_event
    project_hash = get_project_hash(raise_on_fail=True)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/masen/code/reflex-dev/VENV-pre-0.4.5a/lib/python3.12/site-packages/reflex/utils/prerequisites.py", line 449, in get_project_hash
    with open(constants.Reflex.JSON, "r") as file:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '.web/reflex.json'

Specifics (please complete the following information):

• Python Version: 3.12.0
• Reflex Version: 0.4.5a1
• OS: macOS
• Browser (Optional):

Additional context
Seems related to #2786

Workaround is to disable telemetry with TELEMETRY_ENABLED=false

_REF-2256

[masenf]

Fixed via #2881