sensor.history_stats was working in the future (fixes #20571)

[dgomes]

Description:

The sensor.history_stats platform was calculating future statistics which resulted in negative values

Related issue (if applicable): fixes #20571

Pull request in home-assistant.io with documentation (if applicable): home-assistant/home-assistant.io#<home-assistant.io PR number goes here>

Example entry for configuration.yaml (if applicable):

  - platform: history_stats
    name: History Stats test
    entity_id: sensor.test
    state: 'whatever''
    type: time
    end: '{{now().replace(hour=23).replace(minute=0).replace(second=0)}}'
    duration:
      hours: 1

(this only fails before 22h00)

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

If the code does not interact with devices:

• Tests have been added to verify that the new code works.