Deprecate isFluid prop

[tay1orjones]

Discussed in #11971 (comment)

What should we do with the existing isFluid props out there? Deprecate them with a note to use the new component could be a good first step.

I think that makes sense. Once this is merged (or included in this PR), we can mark the isFluid prop as deprecated, noting that the new variant is available as a standalone component.

[tw15egan]

Looking at this now, it seems like isFluid is using context to set whether the control is inside a FluidForm or not. I don't think anything needs to be done as is, there is no isFluid prop being used inside TextInput, just the context references. I don't think there is much we can do until V12, where we just remove these references from TextInput and simplify the FluidForm logic to just always have that class (cds--form--fluid)

[tw15egan]

However, this did make me realize that our current implementation won't work as is, as each FluidTextnput is creating its own Form wrapper. I will make some changes to the original PR (#11971)

[tay1orjones]

That makes sense, I'll close this one