fix(toolbar): stop the block drag preview hardcoding a weight its label does not use

Third instance of the same mirror drift, found by sweeping rather than
waiting for it to be reported. The toolbar item label renders at the
inherited 400 (its container is `chipVariants`, which is weight-free), but
the drag preview hardcoded `font-weight: 500` — so the preview never matched
the item it previews, before or after this PR.

Drops the weight only. The 16px is left alone: a drag preview reading larger
than its source is a deliberate affordance, not a mismatch.

Not fixed here, deliberately: the `font-weight: 500` in code-editor.tsx's
highlight layer. That HTML is rendered in registration with a transparent
textarea, so weight affects glyph advance widths and the caret alignment —
it needs live in-editor verification, unlike a detached drag ghost. Its two
placeholder branches already disagree on weight, so it wants its own change.

Author: waleedlatif1

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/toolbar/components/drag-preview.ts

@@ -58,7 +58,6 @@ export function createDragPreview(info: DragItemInfo): HTMLElement {
   text.style.cssText = `
     color: var(--text-primary);
     font-size: 16px;
-    font-weight: 500;
     white-space: nowrap;
     overflow: hidden;
     text-overflow: ellipsis;