chore: bump signature_pad from 2.3.2 to 5.0.4 in /webapp

Bumps [signature_pad](https://github.com/szimek/signature_pad) from 2.3.2 to 5.0.4.
- [Release notes](https://github.com/szimek/signature_pad/releases)
- [Changelog](https://github.com/szimek/signature_pad/blob/master/CHANGELOG.md)
- [Commits](https://github.com/szimek/signature_pad/commits/v5.0.4)

---
updated-dependencies:
- dependency-name: signature_pad
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

webapp/package.json

@@ -59,7 +59,7 @@
     "pojo2xml": "^1.7.2",
     "rxjs": "^7.8.1",
     "select2": "4.0.3",
-    "signature_pad": "2.3.x",
+    "signature_pad": "5.0.x",
     "tslib": "^2.5.3",
     "zone.js": "^0.14.4"
   },