fix: Rendering of empty data table cells (#171)

* polish null/undefined value check in data table rendering

* fix: fix empty data table cell rendering min-height

* drop unnecessary empty string fallback

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

* lint

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: jankuca

src/webviews/webview-side/dataframe-renderer/DataframeRenderer.tsx

@@ -153,13 +153,13 @@ export const DataframeRenderer = memo(function DataframeRenderer({
                                     {rows.map((value, index) => (
                                         <div
                                             key={index.toString()}
-                                            className={`p-[4px] border-b border-r border-[var(--vscode-panel-border)] font-mono ${
+                                            className={`p-[4px] min-h-[16px] border-b border-r border-[var(--vscode-panel-border)] font-mono ${
                                                 index % 2 === 0
                                                     ? 'bg-[var(--vscode-editor-background)]'
                                                     : 'bg-[var(--vscode-list-hoverBackground)]/50'
                                             }`}
                                         >
-                                            {value === null || value === undefined ? 'None' : String(value)}
+                                            {value == null ? 'None' : String(value)}
                                         </div>
                                     ))}
                                 </div>