Specimen page: "Select preview text" dropdown labels overlap with selected values

#This issue also works for requesting features.

**Describe the issue**
On the Specimen page for any font (e.g., Geist), the "Select preview text"
dropdowns show overlapping text — the placeholder label and the selected
value are both rendered simultaneously, causing them to visually collide.

**To Reproduce**
1. Go to https://fonts.google.com/specimen/Geist
2. Click on the "Specimen" tab
3. Observe the two dropdowns under "Select preview text"
4. The first dropdown shows something like "SWriting systemng syster"
and the second shows "SLanguagelanguage" — both texts overlap each other.

**Expected behavior**
The dropdown should display only the selected value (or placeholder)
at a time — not both overlaid on top of each other.

**Additional context**
- OS: Windows 11
- Browser: Zen (Firefox based)

**Screenshots**