testing/elementary-photos: remove rest from makedepends, enable on loongarch64

This isn't needed anymore since version 8.0.0

Ref https://github.com/elementary/photos/pull/746/files#diff-b803fcb7f17ed9235f1e5cb1fcd2f5d3b2838429d4368ae4c57ce4436577f03f

testing/elementary-photos/APKBUILD

@@ -6,8 +6,7 @@ pkgrel=0
 pkgdesc="Photo viewer and organizer designed for elementary OS"
 url="https://github.com/elementary/photos"
 # riscv64, s390x: blocked by libhandy1
-# loongarch64: blocked by rest
-arch="all !riscv64 !s390x !loongarch64"
+arch="all !riscv64 !s390x"
 license="LGPL-2.1"
 depends="hicolor-icon-theme"
 makedepends="
@@ -30,7 +29,6 @@ makedepends="
 	libwebp-dev
 	libxml2-dev
 	meson
-	rest-dev
 	sqlite-dev
 	vala
 	"