Fix T88375: Bone Size Small After V3D.View_All

The wrong matrix function was used and overwrote the custom bone shape
scale instead of reading from it.

Reviewed By: sybren

Differential Revision: https://developer.blender.org/D11330

source/blender/blenkernel/intern/armature.c

@@ -2882,7 +2882,7 @@ bool BKE_pose_minmax(Object *ob, float r_min[3], float r_max[3], bool use_hidden
         if (bb_custom) {
           float mat[4][4], smat[4][4];
           scale_m4_fl(smat, PCHAN_CUSTOM_BONE_LENGTH(pchan));
-          mul_m4_v3(smat, pchan->custom_scale_xyz);
+          rescale_m4(smat, pchan->custom_scale_xyz);
           mul_m4_series(mat, ob->obmat, pchan_tx->pose_mat, smat);
           BKE_boundbox_minmax(bb_custom, mat, r_min, r_max);
         }