## 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
def __init__(self, klass):
        self.klass = klass
        self.instance = None
    def __call__(self, *args, **kwds):
        if self.instance is None:
            self.instance = self.klass(*args, **kwds)
        return self.instance
def get_machine_id() -> str:
    """A MAC address-dependent ID. Useful for PostHog instance analytics."""
    
    
    return hashlib.md5(uuid.getnode().to_bytes(6, "little")).hexdigest()
def get_table_size(table_name) -> str:
    from django.db import connection
    query = (
        f'SELECT pg_size_pretty(pg_total_relation_size(relid)) AS "size" '
        f"FROM pg_catalog.pg_statio_user_tables "
        f"WHERE relname = '{table_name}'"
    )
    cursor = connection.cursor()
    cursor.execute(query)
    return dict_from_cursor_fetchall(cursor)[0]["size"]
def get_table_approx_count(table_name) -> str:
    from django.db import connection
    query = f"SELECT reltuples::BIGINT as \"approx_count\" FROM pg_class WHERE relname = '{table_name}'"
    cursor = connection.cursor()
    cursor.execute(query)
    return compact_number(dict_from_cursor_fetchall(cursor)[0]["approx_count"])
def compact_number(value: Union[int, float]) -> str: