Fix the build and clang-tidy failures in the persistence change

The round-trip test named a TextureTileMethod enumerator that does not
exist (MirroredRepeat, not Mirror) and used a bare Approx, which Catch2 v3
keeps in its own namespace. The rest of the file compares floats with
WithinAbs, so these follow it rather than reaching for Catch::Approx.

bbs_3mf.cpp reads and writes the layer JSON but picked up the declarations
through another header, and the same for boost::to_lower.

src/libslic3r/Format/bbs_3mf.cpp

@@ -21,6 +21,7 @@
 #include "libslic3r/BrimEarsPoint.hpp"
 #include "libslic3r/Config.hpp"
 #include "libslic3r/CustomGCode.hpp"
+#include "libslic3r/TextureDisplacement.hpp"
 #include "libslic3r_version.h"
 
 #include "bbs_3mf.hpp"
@@ -32,6 +33,7 @@
 #include <boost/spirit/home/qi/numeric/int.hpp>
 #include <cstdlib>
 #include <cstddef>
+#include <boost/algorithm/string/case_conv.hpp>
 #include <boost/algorithm/string/constants.hpp>
 #include <algorithm>
 #include <boost/thread/lock_types.hpp>