## Bug description

The grouped-by-month view in charts is hella confusing. The x-axis shows a date that does not reflect the value on the y-axis.

1. the y-axis shows the number for the END of the month
2. the x-axis reads as "beginning of the month"

![CleanShot 2024-02-05 at 10 23 30@2x](https://github.com/PostHog/posthog/assets/35429197/d78df745-8319-4b78-95fa-d96f18aee357)

### Comparison with daily grouping

Compare the "group by month" view with "group by day". The x-axis labeling aligns with the y-axis values. 

![CleanShot 2024-02-05 at 10 29 20@2x](https://github.com/PostHog/posthog/assets/35429197/998825fa-7406-4214-8310-8f173980f80c)


## How to reproduce

1. Group a chart by month 
2. select "unique events"

## Proposal 

### 1. easy fix - remove the "1." from the labelling

- will still confuse readers with "is this the beginning or end of the month"

![CleanShot 2024-02-05 at 10 23 30@2x](https://github.com/PostHog/posthog/assets/35429197/1a0ae6d4-0e02-4b32-86ab-7b0e069655ed)

### 2. correct fix - show end of month

- removes ambiguity from "is that the beginning or end of month"
- harder to implement because months have different end days

![CleanShot 2024-02-05 at 10 23 30@2x](https://github.com/PostHog/posthog/assets/35429197/61226346-7f97-4bcd-87bf-53fc83c75245)


cc @jannesblobel
posthog/utils.py
at_location = email.find("@")
        if at_location == -1:
            return False
        return self.emails.get(email[(at_location + 1) :], False)
@lru_cache(maxsize=1)
def get_available_timezones_with_offsets() -> Dict[str, float]:
    now = dt.datetime.now()
    result = {}
    for tz in pytz.common_timezones:
        try:
            offset = pytz.timezone(tz).utcoffset(now)
        except Exception:
            offset = pytz.timezone(tz).utcoffset(now + dt.timedelta(hours=2))
        offset_hours = int(offset.total_seconds()) / 3600
        result[tz] = offset_hours
    return result
def refresh_requested_by_client(request: Request) -> bool:
    return _request_has_key_set("refresh", request)
def _request_has_key_set(key: str, request: Request) -> bool:
    query_param = request.query_params.get(key)
    data_value = request.data.get(key)
    return (query_param is not None and (query_param == "" or query_param.lower() == "true")) or data_value is True
def str_to_bool(value: Any) -> bool:
    """Return whether the provided string (or any value really) represents true. Otherwise, false.
    Just like plugin server stringToBoolean.
    """
    if not value:
        return False
    return str(value).lower() in ("y", "yes", "t", "true", "on", "1")
def get_helm_info_env() -> dict: