[jpegli] Fix assertion for refinement bits

The num_refinement_bits is an upper bound for the allocation required.

For luma-only refinement this equality always holds. But when chroma refinement is involved, then some scans may not use up the entire allocation.

lib/jpegli/entropy_coding.cc

@@ -487,7 +487,7 @@ void TokenizeJpeg(j_compress_ptr cinfo) {
         new_refinement_bits += sti->num_nonzeros;
       }
     }
-    JXL_DASSERT(m->next_refinement_bit ==
+    JXL_DASSERT(m->next_refinement_bit <=
                 refinement_bits + num_refinement_bits);
     num_refinement_bits += new_refinement_bits;
   }