Merge "Signed-off-by: Yusuke <yusuke.furuya@rakuten.com> Add: MMS config file for Rakuten Mobile MNO" am: 594aaaf10d am: bb219ee2ef am: ec4773c514

Original change: https://android-review.googlesource.com/c/platform/packages/apps/Messaging/+/1615180

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I8a6c01b7ee63a6bde17c49075cf31fd8f41eb6d8