Overpass: Inaccurate diacritics rendering

**Describe the bug**
The Overpass font currently served renders some characters (e.g. the Grave Accent (U+0060) and Middle Dot (U+00B7)) as zero-width combining diacritics rather than spacing characters.

When used in standard text, the backtick combines with the following letter (e.g., placing a grave accent over it) instead of standing alone. Similarly, the middle dot overlaps or stacks with adjacent characters instead of occupying its own space.

**To Reproduce**

1. Go to [Google Fonts: Overpass](https://fonts.google.com/specimen/Overpass)
2. Type the string: ``` ``test`` ```
3. Type the string: ``` 1···2 ```
4. Observe that the first backtick overlaps with the second and renders on top of the "t", and the middle dots also overlap.

**Expected behavior**

* The **Grave Accent / Backtick (`U+0060`)** should display as a standalone spacing character (not a combining dead key).
* The **Middle Dot (`U+00B7`)** should display as a standalone punctuation mark with horizontal spacing.

**Additional context**

* **Font Name:** Overpass
* **Platform:** Google Fonts (Web)
* **Characters Affected:** U+0060 (Grave Accent), U+00B7 (Middle Dot)

* **Notes:**
- This issue has been noted in the upstream repo (RedHatOfficial/Overpass#95).
- This issue doesn't exist in the Overpass website that uses the standalone `otf`s, it's a problem with the variable weight font only.
- Overpass Mono is unaffected