## 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/hogql_queries/insights/lifecycle_query_runner.py
event_filters.append(action_to_expr(action))
                elif isinstance(serie, EventsNode):
                    if serie.event is not None:
                        event_filters.append(
                            ast.CompareOperation(
                                op=ast.CompareOperationOp.Eq,
                                left=ast.Field(chain=["event"]),
                                right=ast.Constant(value=str(serie.event)),
                            )
                        )
                else:
                    raise ValueError(f"Invalid serie kind: {serie.kind}")
                if serie.properties is not None and serie.properties != []:
                    event_filters.append(property_to_expr(serie.properties, self.team))
        with self.timings.measure("test_account_filters"):
            if (
                self.query.filterTestAccounts
                and isinstance(self.team.test_account_filters, list)
                and len(self.team.test_account_filters) > 0
            ):
                for property in self.team.test_account_filters:
                    event_filters.append(property_to_expr(property, self.team))
        if len(event_filters) == 0:
            return ast.Constant(value=True)
        elif len(event_filters) == 1:
            return event_filters[0]
        else:
            return ast.And(exprs=event_filters)
    @cached_property
    def events_query(self):