Set SOVERSION 1 for Apple builds to match Linux library versioning (#28101)

### Description

Include Apple in the existing `SOVERSION 1` block by changing the CMake
condition from `if(NOT APPLE AND NOT WIN32)` to `if(NOT WIN32)`.

**Before:** macOS install name is `@rpath/libonnxruntime.1.20.0.dylib` —
dependents pinned to exact version.
**After:** macOS install name is `@rpath/libonnxruntime.1.dylib` —
dependents only require major version, matching Linux
`libonnxruntime.so.1`.

The actual library file remains `libonnxruntime.<VERSION>.dylib`, so
existing packaging scripts (`copy_strip_binary.sh`,
`mac-cpu-packaging-steps.yml`, `js/node/CMakeLists.txt`) are unaffected.
CMake creates the intermediate `libonnxruntime.1.dylib` symlink
automatically.

### Motivation and Context

On macOS, linking against onnxruntime embeds the full-versioned install
name, causing `dlopen` failures when a different patch version is
installed:

```
dlopen(dependent.dylib, 0x0001): Library not loaded: @rpath/libonnxruntime.1.20.0.dylib
```

Linux already avoids this via `SOVERSION 1`. The exclusion of Apple from
that code path appears unintentional.

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: tianleiwu <30328909+tianleiwu@users.noreply.github.com>

Author: Copilot

cmake/onnxruntime.cmake

@@ -286,7 +286,7 @@ if(WIN32)
   target_link_options(onnxruntime PRIVATE ${onnxruntime_DELAYLOAD_FLAGS})
 endif()
 #See: https://cmake.org/cmake/help/latest/prop_tgt/SOVERSION.html
-if(NOT APPLE AND NOT WIN32)
+if(NOT WIN32)
   if(CMAKE_SYSTEM_NAME MATCHES "AIX")
     set_target_properties(onnxruntime PROPERTIES
       PUBLIC_HEADER "${ONNXRUNTIME_PUBLIC_HEADERS}"
@@ -302,7 +302,7 @@ if(NOT APPLE AND NOT WIN32)
       FOLDER "ONNXRuntime")
   endif()
 else()
-  # Omit the SOVERSION setting in Windows/macOS/iOS/.. build
+  # Omit the SOVERSION setting in Windows build
   set_target_properties(onnxruntime PROPERTIES
     PUBLIC_HEADER "${ONNXRUNTIME_PUBLIC_HEADERS}"
     LINK_DEPENDS ${SYMBOL_FILE}