[fftw3] Suppress "`vcpkg_cmake_configure` already called" warnings from `fftw3f` and `fftw3l`

### Is your feature request related to a problem? Please describe.

Currently, the `fftw3` port generates and builds three configurations (`fftw3`, `fftw3f`, and `fftw3l`) automatically. However, because each one calls `vcpkg_cmake_configure`, vcpkg spits out a warning that `vcpkg_cmake_configure` has already been called for even though `fftw3f` and `fftw3l` are actually practically distinct from `fftw3`. These warnings dirty the toolchain/build logs. In practice this is a minor issue, but would be nice to fix

### Proposed solution

I see three potential solutions:
A) Suppress the warnings within the port (I'm not sure this is actually possible, but would be the simplest solution. This may require adding a new option to `vcpkg_cmake_configure` to make this possible)
B) Split `fftw3` into three separate ports: `fftw3`, `fftw3f`, and `fftw3l` (downside is this may end up causing the `fftw` distfile to be downloaded redundantly)
C) Remove the need to configure and build `fftw3`, `fftw3f`, and `fftw3l` separately (I.e., configure and build them together, so there's only one call to `vcpkg_cmake_configure`)

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start by locating the fftw3 port and its three vcpkg_cmake_configure calls, then read the helper's warning behavior. Determine which of the proposed approaches is acceptable before implementing anything; done should eliminate the redundant warnings while preserving the fftw3, fftw3f, and fftw3l builds.

Written by the indexing model from the issue text.