Remove state class from daily net sensors in DSMR Reader

[frenck]

Proposed change

This PR fixes entities tracking a net total (and not an increasing total) in the DSMR Reader integration. Fixes warnings like:

integration dsmr_reader has state class total_increasing, but its state is not strictly increasing

Causing these not to work with statistics.

Technically, it should be possible to convert these into a total state class with a last_reset; however, these have no value to keep, as this integration already provides sensors with the increasing totals.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes DSMR reader sensor has state class total_increasing, but its state is not strictly increasing #55752
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

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

• Documentation added/updated for www.home-assistant.io

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

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• For the updated dependencies - a link to the changelog, or at minimum a diff between library versions is added to the PR description.
• Untested files have been added to .coveragerc.

The integration reached or maintains the following Integration Quality Scale:

• No score or internal
• 🥈 Silver
• 🥇 Gold
• 🏆 Platinum

To help with the load of incoming pull requests:

• I have reviewed two other open pull requests in this repository.

[probot-home-assistant]

Hey there @depl0y, mind taking a look at this pull request as it has been labeled with an integration (dsmr_reader) you are listed as a code owner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[Glodenox]

The pull request doesn't fully fix the issue. I just ran the updated code locally for a bit and got this error for another entity:
[homeassistant.components.sensor.recorder] Entity sensor.dsmr_reading_electricity_delivered_2 from integration dsmr_reader has state class total_increasing, but its state is not strictly increasing. Triggered by state 15973.350 (15973.351) with last_updated set to 2022-07-28T21:50:39.862644+00:00.. There are also two entities for gas meter values that probably could do without the state class for the same reason.

I had code waiting locally that would prevent the sensor from using data if it was only a tiny bit smaller than the previous value, so the total_increasing class could remain. Just removing the state class seems to not have any negative effect on the visualisation of the data, so I guess that's even better.