docs: Replaced image in L Preview material docs

Change-Id: I7db905f0fc8ae2bf9826d74bc7030d5a41cd2859
diff --git a/docs/html/preview/material/images/list_mail.png b/docs/html/preview/material/images/list_mail.png
index bd107ff..e70291c 100644
--- a/docs/html/preview/material/images/list_mail.png
+++ b/docs/html/preview/material/images/list_mail.png
Binary files differ