Failure when `toMatchSnapshot('file')` has no filename extension specified in `'file'` string

**Describe the bug**

Failure when image snapshot has no filename extension

**To Reproduce**

See https://github.com/microsoft/playwright/issues/13414

**Expected behavior**

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**Screenshots**


**Desktop (please complete the following information):**


**Smartphone (please complete the following information):**


**Additional context**
