branding for about:debugging needs logo SVG

From legacy/trac#30429 (moved)

We need an updated logo for aboutdebugging-firefox-release.svg ... (one can see the issue after flipping devtools.aboutdebugging.new-enabled and then opening about:debugging)

While fixing the above issue for legacy/trac#30429 (moved), we realized that aboutdebugging-firefox-logo.svg also needs to be replaced. It's a black and white logo that will be colorized when the user selects it. For an example see: https://searchfox.org/mozilla-esr68/source/devtools/client/themes/images/aboutdebugging-firefox-logo.svg