Fix UserSVG handling extensionless images as SVGs

[AmoebeLabs]

Description

Version 2.4.4 inadvertently treated extensionless images as SVGs, and tried to inject them, which failed of course.

This has been fixed:

• any image with a different or no extension will be handled by the default image render path
• only SVGs are injected (if svginjection set to true, which is the default)
• if injection fails, a fallback is added: the svginjection option is set to false, and a new render is initiated, which means the image is rendered as an external SVG image (or whatever it is).

Related Issue

Motivation and Context

How Has This Been Tested?

Tested with the person card:

• Person: icon
• Tha Washer: external image from /local/images
• Ricky: from the HA Person object, /api/..../512x512

Screenshots (if appropriate):