refactor: Move integration tests from 'examples/' into 'tests/' (#5367)

This change moves `examples/example` into `tests/conan` to make it clear it is an integration test, and adjusts the `conan` CI job accordingly

tests/conan/src/example.cpp

@@ -0,0 +1,10 @@
+#include <xrpl/protocol/BuildInfo.h>
+
+#include <cstdio>
+
+int
+main(int argc, char const** argv)
+{
+    std::printf("%s\n", ripple::BuildInfo::getVersionString().c_str());
+    return 0;
+}