Allow reconfiguration of integration sensor

[elupus]

Proposed change

Allow changing a riemann sum integral after it's been added from config flow.

Type of change

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Additional information

• This PR fixes or closes issue: fixes #100650
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[home-assistant[bot]]

Hey there @dgomes, mind taking a look at this pull request as it has been labeled with an integration (integration) you are listed as a code owner for? Thanks!

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[dgomes]

I'm OK with adding an option to change the integration method, but:

• We don't allow changing the unit_of_measurement in any other integration, don't think we should do it for this one
• Changing the source sensor might be too much, it changes completely the history and it would be more advisable to create a new helper altogether.

[elupus]

It very easy to get wrong when you initially add it. Also replacing the source sensor is allowed for stuff like group helpers, so see no reason not to add it.

[elupus]

I have removed the scaling and time unit config, as well as making sure the new entity is selected has a compatible unit of measurement.

[home-assistant[bot]]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks :+1:

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