fix: use position fixed for input and textarea in tableeditor

Otherwise when scrolling the table, the input will not appear at
the expected position, and may even appear outside of the view when
the table is bigger than the viewport.

Drawback: the table will resize its columns when the input/textarea
is created (as position: sticky is in the flow). So I've also removed
the width reset.

fix #2071

umap/static/umap/css/tableeditor.css

@@ -56,8 +56,7 @@
 .umap-table-editor textarea,
 .umap-table-editor input[type=text] {
     border-radius: initial;
-    width: initial;
-    position: fixed;
+    position: sticky;
 }
 .umap-table-editor th button {
     transform: rotate(90deg);