Bump matrix-js-sdk from 4.0.0 to 19.7.0

Bumps [matrix-js-sdk](https://github.com/matrix-org/matrix-js-sdk) from 4.0.0 to 19.7.0.
- [Release notes](https://github.com/matrix-org/matrix-js-sdk/releases)
- [Changelog](https://github.com/matrix-org/matrix-js-sdk/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/matrix-org/matrix-js-sdk/compare/v4.0.0...v19.7.0)

---
updated-dependencies:
- dependency-name: matrix-js-sdk
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -125,7 +125,7 @@
     "emoji-picker-react": "^3.1.3",
     "isomorphic-fetch": "^2.2.1",
     "linkifyjs": "^2.1.9",
-    "matrix-js-sdk": "^4.0.0",
+    "matrix-js-sdk": "^19.7.0",
     "node-localstorage": "^2.1.5",
     "olm": "https://packages.matrix.org/npm/olm/olm-3.1.4.tgz",
     "prop-types": "^15.6.2",