Use String8/16 c_str [cas]

Bug: 295394788
Test: make checkbuild
Change-Id: I1faccac8711d5cccee70443548940d99804c7c2a
diff --git a/cas/aidl/default/SharedLibrary.cpp b/cas/aidl/default/SharedLibrary.cpp
index e79f383..c12d17d 100644
--- a/cas/aidl/default/SharedLibrary.cpp
+++ b/cas/aidl/default/SharedLibrary.cpp
@@ -26,7 +26,7 @@
 namespace cas {
 
 SharedLibrary::SharedLibrary(const String8& path) {
-    mLibHandle = dlopen(path.string(), RTLD_NOW);
+    mLibHandle = dlopen(path.c_str(), RTLD_NOW);
 }
 
 SharedLibrary::~SharedLibrary() {