Fix BLE API include directive issue with CY8CKIT-062-BLE

Related to ARMmbed#15483

Implement the `createBLEInstance()` function in `connectivity/FEATURE_BLE/source/cordio/source/BLEInstanceBaseImpl.cpp`.

* Return a valid `BLEInstanceBase` object from the `createBLEInstance()` function.
* Ensure the `createBLEInstance()` function is correctly linked and resolves the undefined reference error.

---

For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/ARMmbed/mbed-os/issues/15483?shareId=XXXX-XXXX-XXXX-XXXX).

connectivity/FEATURE_BLE/source/cordio/source/BLEInstanceBaseImpl.cpp

@@ -773,3 +773,9 @@ FunctionPointerWithContext<::BLE::InitializationCompleteCallbackContext *> BLEIn
 
 } // namespace impl
 } // namespace ble
+
+// Implement the createBLEInstance() function to return a valid BLEInstanceBase object
+ble::BLEInstanceBase *ble::createBLEInstance()
+{
+    return (&(ble::impl::BLEInstanceBase::deviceInstance()));
+}