Raise RuntimeWarning if jax > 0.4.28 is installed

[mudit2812]

Jax is not compatible with pennylane for versions > 0.4.28 (confirmed by the test logs of this PR). This PR raises a RuntimeWarning if version > 0.4.28 is installed:

• In QNode.__init__ if the specified interface resolves to JAX or JAX_JIT
• In execute if the original interface was "auto" or None and the resolved interface is JAX or JAX_JIT. I don't raise a warning if the original interface was jax/jax-jit because if that is the case, QNode.__init__ should've already raised a warning.
• This is done by adding a _validate_jax_version private kwarg to qml.math.get_canonical_interface_name, which is called by QNode.__init__, and qml.workflow.resolution._resolve_interface (used by qml.execute), so that both those entry points can raise warnings if appropriate.

Possible drawbacks:
None. The only annoying is that our CI uses supported versions of jax, so we can't get coverage for the runtime warning. I've added a # pragma: no cover to work around this, but I'm not particularly happy about it.

[sc-82570]

[github-actions]

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Please edit doc/releases/changelog-dev.md with:

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.60%. Comparing base (872607d) to head (2395413).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #6864   +/-   ##
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  Coverage   99.60%   99.60%           
=======================================
  Files         476      476           
  Lines       45182    45195   +13     
=======================================
+ Hits        45002    45015   +13     
  Misses        180      180           

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[albi3ro]

So why are we not validating if someone specifies interface="jax"? Or am I missing something?

[andrijapau]

Wouldn't it be less invasive to do something like,

Suggested change

	self._interface = get_canonical_interface_name(interface, _validate_jax_version=True)
	self._interface = get_canonical_interface_name(interface)
	if "jax" in self.interface:
	_validate_jax_version()

and not have to modify anything downstream. For example, _resolve_interface is called in qml.execute which (with the new changes coming) will only be configurable purely from the QNode with no other entry point. That way I see us only having to verify the version here.