fix: Broken sorting due to typo in jinja template (#614)

Author: BeyondEvil

src/pytest_html/resources/index.jinja2

@@ -61,7 +61,7 @@
       <thead id="results-table-head">
         <tr>
           <th class="sortable" data-column-type="result">Result</th>
-          <th class="sortable" data-column-type="testid">Test</th>
+          <th class="sortable" data-column-type="testId">Test</th>
           <th class="sortable" data-column-type="duration">Duration</th>
           <th>Links</th>
         </tr>