Can't link to dynamic flatcc dependency

For Homebrew and vcpkg, where we can get shared flatcc dependency libraries, the IPC feature can't use the dynamic version of the library. Claude came up with

```path
diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -227,13 +227,13 @@ if(NANOARROW_IPC)

elseif(NOT NANOARROW_FLATCC_INCLUDE_DIR)
set(NANOARROW_FLATCC_INCLUDE_DIR "${NANOARROW_FLATCC_ROOT_DIR}/include")
- add_library(flatccrt STATIC IMPORTED)
+ add_library(flatccrt SHARED IMPORTED)
set_target_properties(flatccrt
PROPERTIES IMPORTED_LOCATION
- "${NANOARROW_FLATCC_ROOT_DIR}/lib/${CMAKE_STATIC_LIBRARY_PREFIX}flatccrt${CMAKE_STATIC_LIBRARY_SUFFIX}"
+ "${NANOARROW_FLATCC_ROOT_DIR}/lib/${CMAKE_SHARED_LIBRARY_PREFIX}flatccrt${CMAKE_SHARED_LIBRARY_SUFFIX}"
IMPORTED_LOCATION_DEBUG
- "${NANOARROW_FLATCC_ROOT_DIR}/debug/lib/${CMAKE_STATIC_LIBRARY_PREFIX}flatccrt_d${CMAKE_STATIC_LIBRARY_SUFFIX}"
+ "${NANOARROW_FLATCC_ROOT_DIR}/debug/lib/${CMAKE_SHARED_LIBRARY_PREFIX}flatccrt_d${CMAKE_SHARED_LIBRARY_SUFFIX}"
IMPORTED_LOCATION_RELEASE
- "${NANOARROW_FLATCC_ROOT_DIR}/lib/${CMAKE_STATIC_LIBRARY_PREFIX}flatccrt${CMAKE_STATIC_LIBRARY_SUFFIX}"
+ "${NANOARROW_FLATCC_ROOT_DIR}/lib/${CMAKE_SHARED_LIBRARY_PREFIX}flatccrt${CMAKE_SHARED_LIBRARY_SUFFIX}"
INTERFACE_INCLUDE_DIRECTORIES
"${NANOARROW_FLATCC_INCLUDE_DIR}")
```

for Homebrew but there may be a better solution.

Start in CMakeLists.txt around the NANOARROW_IPC configuration and the flatccrt imported-target setup. Reproduce the Homebrew or vcpkg configuration with a shared flatcc dependency, then inspect how the target is located and linked. Done means the IPC feature configures and links successfully against the dynamic flatcc library in those environments.

Written by the indexing model from the issue text.