Make set_value required in number template

[joostlek]

Proposed change

Make set_value required in number template as mentioned by @MartinHjelmare in #121849 (comment)

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[home-assistant]

Hey there @PhracturedBlue, @tetienne, @home-assistant/core, mind taking a look at this pull request as it has been labeled with an integration (template) you are listed as a code owner for? Thanks!

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[MartinHjelmare]

Side note: We may want to make CONF_STATE optional and set the native value optimistically if no state value template is set. We have that pattern in other template platforms.

[joostlek]

native value optimistically

What do you mean with this?

[MartinHjelmare]

Like this:

core/homeassistant/components/template/number.py

Lines 207 to 209 in f394dfb

	if self._optimistic:
	self._attr_native_value = value
	self.async_write_ha_state()

[MartinHjelmare]

Thanks!

[epenet]

Note: CI is failing