Mm-20223 Add webp emoji support (#20283)

* Added webp package into app/emoji.go , also added a test

* fixed import order inside emoji.go

* Ran go mod tidy

* Conversion to png for Webp emojis that must be resized is implemented

* Deleted unused import

* Added reading mechanism for webp instead of creating

* fileutils and filepath are used while reading a webp file during test

* Deleted readtestwebp function and put it in emoji_test as requested

* Added webp image upload test inside api4/file_test.go

* Expect image is changed from false to true

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

api4/file_test.go

@@ -453,6 +453,17 @@ func TestUploadFiles(t *testing.T) {
 			expectedImageMiniPreview: []bool{false},
 			expectedCreatorId:        th.BasicUser.Id,
 		},
+		// Webp image test
+		{
+			title:                    "Webp image",
+			names:                    []string{"testwebp.webp"},
+			expectImage:              true,
+			expectedImageWidths:      []int{128},
+			expectedImageHeights:     []int{256},
+			expectedImageHasPreview:  []bool{true},
+			expectedCreatorId:        th.BasicUser.Id,
+			expectedImageMiniPreview: []bool{true},
+		},
 		// Error cases
 		{
 			title:                 "Error channel_id does not exist",