Issue described in https://github.com/vector-im/riot-web/issues/9690.
With certain `window.devicePixelRatio` values
(e.g. `1.5789473684210527`), the calculated thumb width/height
would be a non-integer value.
Passing such values to `client.mxcUrlToHttp()` causes it to
generate URLs to the thumbnail API with non-integer values.
As per the spec, non-integer values are forbidden for that API and a
400 HTTP response is returned (`Query parameter b'width' must be an
integer`).
Fixing matrix-js-sdk's `mxcUrlToHttp()` to sanitize such values
would also be a good idea and likely fix more than just matrix-react-sdk
and riot-web. Still, it feels like matrix-react-sdk should play nice
as well, and not request thumbnails for weird widths/heights.
Signed-off-by: Slavi Pantaleev <slavi@devture.com>
