build(deps): bump pdfjs-viewer-element from 2.5.4 to 2.7.4

Bumps [pdfjs-viewer-element](https://github.com/alekswebnet/pdfjs-viewer-element) from 2.5.4 to 2.7.4.
- [Release notes](https://github.com/alekswebnet/pdfjs-viewer-element/releases)
- [Commits](missing-elements/pdfjs-viewer@v.2.5.4...v2.7.4)

---
updated-dependencies:
- dependency-name: pdfjs-viewer-element
  dependency-version: 2.7.4
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

package.json

@@ -44,7 +44,7 @@
         "moment": "^2.18.1",
         "numeral": "^2.0.6",
         "parsleyjs": "^2.7.2",
-        "pdfjs-viewer-element": "2.5.4",
+        "pdfjs-viewer-element": "2.7.4",
         "poly2tri": "^1.5.0",
         "popper.js": "^1.16.1",
         "protobufjs": "7.2.5",