could you backport memory leak fix for mate-panel to debian 10?

[张 宁 <zhangn1985@outlook.com>]

Dear Debian Mate team

recently big progress in mate-panel, a lot of memory leak fixed. could you backport them to debian 10?

upstream bug: https://github.com/mate-desktop/mate-panel/issues/1085
github PRs: https://github.com/mate-desktop/mate-panel/pull/1112 https://github.com/mate-desktop/mate-panel/pull/1113

Thanks.
Ning.