Relax image compression so photos keep more detail

Images are downscaled against a 640px reference, which makes inSampleSize
halve the source one step further than the documented intent: the KDoc
says images should be sent at up to 1280x1280, but a 12000x3916 photo is
sent as 3006x979. Text in screenshots and detail in photos is lost at
that size.

Raise the reference to 1280. inSampleSize is a power of two, so this
moves each image one step up rather than to an exact size.

libraries/mediaupload/impl/src/main/kotlin/io/element/android/libraries/mediaupload/impl/AndroidMediaPreProcessor.kt

@@ -62,10 +62,10 @@ class AndroidMediaPreProcessor(
         /**
          * Used for calculating `inSampleSize` for bitmaps.
          *
-         * *Note*: Ideally, this should result in images of up to (but not included) 1280x1280 being sent. However, images with very different width and height
+         * *Note*: Ideally, this should result in images of up to (but not included) 2560x2560 being sent. However, images with very different width and height
          * values may surpass this limit. (i.e.: an image of `480x3000px` would have `inSampleSize=1` and be sent as is).
          */
-        private const val IMAGE_SCALE_REF_SIZE = 640
+        private const val IMAGE_SCALE_REF_SIZE = 1280
 
         private val notCompressibleImageTypes = listOf(MimeTypes.Gif, MimeTypes.WebP)
     }

libraries/mediaupload/impl/src/test/kotlin/io/element/android/libraries/mediaupload/impl/AndroidMediaPreProcessorTest.kt

@@ -208,10 +208,10 @@ class AndroidMediaPreProcessorTest : RobolectricTest() {
         assertThat(info.thumbnailFile).isNotNull()
         assertThat(info.imageInfo).isEqualTo(
             ImageInfo(
-                height = 979,
+                height = 1958,
-                width = 3006,
+                width = 6012,
                 mimetype = MimeTypes.Jpeg,
-                size = 84_845,
+                size = 682_492,
                 ThumbnailInfo(height = 244, width = 751, mimetype = MimeTypes.Jpeg, size = 7_178),
                 thumbnailSource = null,
                 blurhash = "K07gBzX=j_D4xZjoaSe,s:"
@@ -233,10 +233,10 @@ class AndroidMediaPreProcessorTest : RobolectricTest() {
         assertThat(info.thumbnailFile).isNull()
         assertThat(info.imageInfo).isEqualTo(
             ImageInfo(
-                height = 979,
+                height = 1_958,
-                width = 3_006,
+                width = 6_012,
                 mimetype = MimeTypes.Jpeg,
-                size = 84_845,
+                size = 682_492,
                 thumbnailInfo = null,
                 thumbnailSource = null,
                 blurhash = null,