fix($sanitize): consider `size` attribute as valid/allowed attribute
fix($sanitize): consider `size` attribute as valid/allowed attribute

The "size" attribute gets set on <font> elements when using HTML5 rich
text editors, or elements with the contenteditable attribute, that rely
on the 'fontSize' command (execCommand).

Closes #5522

ammula88/angular.js,ammula88/angular.js,ammula88/angular.js,ammula88/angular.js,ammula88/angular.js