fix: remove floating search button that overlaps chat widget

The search-button class uses position:fixed in Just the Docs CSS so
moving it in the DOM has no effect. Removed entirely since the search
input is already present in the header.

Author: neuromechanist

_layouts/default.html

@@ -79,11 +79,6 @@
           </div>
           <div id="search-results" class="search-results"></div>
         </div>
-        {% if site.search.button %}
-          <a href="#" id="search-button" class="search-button">
-            <svg viewBox="0 0 24 24" class="icon"><use xlink:href="#svg-search"></use></svg>
-          </a>
-        {% endif %}
       {% endif %}
       {% include header_custom.html %}
       {% if site.aux_links %}