## Is your feature request related to a problem?

When sending incorrectly formatted payloads (e.g. a text-based string with a `gzip` compression header), the app will fail with a cryptic 500 error and register an unhandled exception.

## Describe the solution you'd like
The app should return a 400 bad request error, with details on why the request failed (i.e. it is incorrectly formatted or the content does not match the compression specified). In addition, this shouldn't be treated as an unhandled exception as it's a client error.


## Describe alternatives you've considered
Keep returning a cryptic 500 error.


## Additional context
Relevant context on #2701


#### *Thank you* for your feature request – we love each and every one!

posthog/settings.py
# True if ingesting with the plugin server into Postgres, as it's then not possible to calculate the mapping on the fly
ASYNC_EVENT_ACTION_MAPPING = PRIMARY_DB == RDBMS.POSTGRES and get_from_env(
    "ASYNC_EVENT_ACTION_MAPPING", True, type_cast=strtobool
)
ACTION_EVENT_MAPPING_INTERVAL_SECONDS = get_from_env("ACTION_EVENT_MAPPING_INTERVAL_SECONDS", 300, type_cast=int)
ASYNC_EVENT_PROPERTY_USAGE = get_from_env("ASYNC_EVENT_PROPERTY_USAGE", False, type_cast=strtobool)
EVENT_PROPERTY_USAGE_INTERVAL_SECONDS = get_from_env(
    "ASYNC_EVENT_PROPERTY_USAGE_INTERVAL_SECONDS", 60 * 60, type_cast=int
)
UPDATE_CACHED_DASHBOARD_ITEMS_INTERVAL_SECONDS = get_from_env(
    "UPDATE_CACHED_DASHBOARD_ITEMS_INTERVAL_SECONDS", 90, type_cast=int
)
# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/2.2/howto/deployment/checklist/
DEFAULT_SECRET_KEY = "<randomly generated secret key>"
# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = os.getenv("SECRET_KEY", DEFAULT_SECRET_KEY)
ALLOWED_HOSTS = get_list(os.getenv("ALLOWED_HOSTS", "*"))
# Metrics - StatsD
STATSD_HOST = os.getenv("STATSD_HOST")
STATSD_PORT = os.getenv("STATSD_PORT", 8125)
STATSD_PREFIX = os.getenv("STATSD_PREFIX", "")
# django-axes settings to lockout after too many attempts
AXES_ENABLED = get_from_env("AXES_ENABLED", True, type_cast=strtobool)
AXES_FAILURE_LIMIT = int(os.getenv("AXES_FAILURE_LIMIT", 5))
AXES_COOLOFF_TIME = timedelta(minutes=15)
AXES_LOCKOUT_CALLABLE = "posthog.api.authentication.axess_logout"
AXES_META_PRECEDENCE_ORDER = [
    "HTTP_X_FORWARDED_FOR",
    "REMOTE_ADDR",