Refreshed design for ngx-leaflet logo to be in line with new Angular brand

[jjmhalew]

Since Angular 17 was announced last year, Angular has a new brand. They encourage the community to adapt their logo to their branding and they provided guidelines, see https://angular.dev/press-kit.

I thought I could help with a new logo according to Angular's new brand guidelines. The logo is visible below, I hope it can help :)