Send SVG images as files (#4595)

Since Android doesn't have support for SVG files we can't create a thumbnail or get the dimensions and other metadata needed for the `m.image` message type, so we need to send them as plain files

libraries/core/src/main/kotlin/io/element/android/libraries/core/mimetype/MimeTypes.kt

@@ -24,6 +24,7 @@ object MimeTypes {
     const val Jpeg = "image/jpeg"
     const val Gif = "image/gif"
     const val WebP = "image/webp"
+    const val Svg = "image/svg+xml"
 
     const val Videos = "video/*"
     const val Mp4 = "video/mp4"