tree-wide: convert dlopen_*() callers to DLOPEN_* wrapper macros

Switch the executable-owned call sites from the plain dlopen_<lib>()
helpers to the new DLOPEN_<LIB>() macros, so that each binary that loads
an optional library at runtime now carries its own .note.dlopen note
instead of relying solely on libsystemd-shared. Each call site passes a
priority reflecting whether it hard-depends on the library (required) or
degrades gracefully without it (recommended).

Co-developed-by: Claude Opus 4.8 <noreply@anthropic.com>

src/tmpfiles/tmpfiles.c

@@ -1267,7 +1267,7 @@ static int parse_acl_cond_exec(
         assert(cond_exec);
         assert(ret);
 
-        r = dlopen_libacl(LOG_DEBUG);
+        r = DLOPEN_LIBACL(LOG_DEBUG, SD_ELF_NOTE_DLOPEN_PRIORITY_RECOMMENDED);
         if (r < 0)
                 return r;
 
@@ -1386,7 +1386,7 @@ static int path_set_acl(
 
         assert(c);
 
-        r = dlopen_libacl(LOG_DEBUG);
+        r = DLOPEN_LIBACL(LOG_DEBUG, SD_ELF_NOTE_DLOPEN_PRIORITY_RECOMMENDED);
         if (r < 0)
                 return r;