add support for exporting and importing props (#14034)

* add support for exporting and importing props

* merge master

* add export test for post props

* add check if postData exists

* add import tests for post props

* fix ci bot issues

Co-Authored-By: Bot from GolangCI <42910462+golangcibot@users.noreply.github.com>

* fix gofmt errors

* remove test comment and add name instead

* remove uneccessary changes

Co-authored-by: Bot from GolangCI <42910462+golangcibot@users.noreply.github.com>

app/export_converters.go

@@ -156,6 +156,7 @@ func ImportLineForPost(post *model.PostForExport) *LineImportData {
 			Channel:  &post.ChannelName,
 			User:     &post.Username,
 			Message:  &post.Message,
+			Props:    &post.Props,
 			CreateAt: &post.CreateAt,
 		},
 	}
@@ -172,6 +173,7 @@ func ImportLineForDirectPost(post *model.DirectPostForExport) *LineImportData {
 			ChannelMembers: &channelMembers,
 			User:           &post.User,
 			Message:        &post.Message,
+			Props:          &post.Props,
 			CreateAt:       &post.CreateAt,
 		},
 	}