Add dispatches for Real Op

[jessegrabowski]

We have no coverage for this Op because it doesn't have an nfunc_name. There was a concern that because numpy returns a view, we could end up with graph mutations that pytensor is not aware of. An example is:

import pytensor.tensor as pt
x = pt.dvector('x')
out = x.real[0].set(99.0)

I added some checks for this specific case, it seems like everything works ok?

[ricardoV94]

the input mutation is not a concern in jax which never does Inplace by default. Your test isn't strong enough because the compare py and numba (or other backend) run minimal rewrites

you need to pass the fully fledged mode as an argument or even simpler test with an already inplace set subtensor (pass inplace=true to the test) and then call the function again