[Bug]: Storage metrics page shows "Invalid number" for some cameras

[leccelecce]

Checklist

• I have updated to the latest available Frigate version.
• I have cleared the cache of my browser.
• I have tried a different browser to see if it is related to my browser.
• I have tried reproducing the issue in incognito mode to rule out problems with any third party extensions or plugins I have installed.

Describe the problem you are having

/api/recordings/storage can return usage: null if there are no recordings, resulting in "Invalid number" being displayed in the UI.

Steps to reproduce

1. Have a camera with no recordings
2. View the system metrics page

Version

0.15.0-4ff0c8a

In which browser(s) are you experiencing the issue with?

No response

Frigate config file

n/a

docker-compose file or Docker CLI command

n/a

Relevant Frigate log output

n/a

Relevant go2rtc log output

n/a

Operating system

Debian

Install method

Docker Compose

Network connection

Wired

Camera make and model

n/a

Screenshots of the Frigate UI's System metrics pages

Provided

Any other information that may be helpful

No response

[hawkeye217]

Fixed in #14587

[leccelecce]

confirmed fixed, thanks!