fix: rendering of 404 page (SQCORE-1347)

[comawill]

SQCORE-1347 [webapp] 404 page does not render correctly

---

PR Submission Checklist for internal contributors

• The PR Title

  • [x] conforms to the style of semantic commits messages¹ supported in Wire's Github Workflow²
  • [x] contains a reference JIRA issue number like SQPIT-764
  • [x] answers the question: If merged, this PR will: ... ³

• The PR Description

  • [x] is free of optional paragraphs and you have filled the relevant parts to the best of your ability

---

What's new in this PR?

Issues

Some text on the 404 page is rendered in white (on a white background)

Solutions

Set font color to black.

Testing

How to Test

open a non existing page on the webapp (e.g. https://wire-webapp-staging.wire.com/404) and make sure all text is readable and a Wire logo is shown.

---

PR Post Submission Checklist for internal contributors (Optional)

• [ ] Wire's Github Workflow has automatically linked the PR to a JIRA issue

---

References

1. https://sparkbox.com/foundry/semantic_commit_messages
2. https://github.com/wireapp/.github#usage
3. E.g. feat(conversation-list): Sort conversations by most emojis in the title #SQPIT-764.

[codecov[bot]]

Codecov Report

Merging #13457 (24ce430) into dev (bc01a11) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev   #13457   +/-   ##
=======================================
  Coverage   39.89%   39.89%           
=======================================
  Files         574      574           
  Lines       20808    20808           
  Branches     4466     4466           
=======================================
  Hits         8301     8301           
  Misses      11503    11503           
  Partials     1004     1004