Always return `t` from use-package pre/post hooks.

Hooks that don't do this will prevent any further configuration of the package.

Docs: 53bf803f1d/use-package.el (L125)
Context: https://github.com/syl20bnr/spacemacs/pull/8543/files#r106792261

core/core-use-package-ext.el

@@ -44,7 +44,7 @@ override lazy-loaded settings."
           (let ((hook (intern (format "use-package--%S--%s-hook"
                                       name-symbol
                                       (substring (format "%s" keyword) 1)))))
-            (push `(add-hook ',hook (lambda nil ,@body)) expanded-forms)))))
+            (push `(add-hook ',hook (lambda nil ,@body t)) expanded-forms)))))
     `(progn ,@expanded-forms)))
 
 (provide 'core-use-package-ext)