fix(lib): prefer `xsel` over `xclip` in clipboard.zsh
fix(lib): prefer `xsel` over `xclip` in clipboard.zsh

See #10925

hoggarth/oh-my-zsh,aaronbieber/oh-my-zsh,ttelford/oh-my-zsh,erwinvaneijk/oh-my-zsh,dpoggi/oh-my-zsh,upperbounds/oh-my-zsh,drench/oh-my-zsh,krafczyk/oh-my-zsh,RavuAlHemio/oh-my-zsh,upperbounds/oh-my-zsh,CromFr/crom-custom-oh-my-zsh,matthewberryman/oh-my-zsh,tonydeng/oh-my-zsh,data219/oh-my-zsh,cristianstu/oh-my-zsh,drench/oh-my-zsh,honnix/oh-my-zsh,moul/oh-my-zsh,honnix/oh-my-zsh,CromFr/crom-custom-oh-my-zsh,moul/oh-my-zsh,dpoggi/oh-my-zsh,kancelott/oh-my-zsh,kancelott/oh-my-zsh,leafty/oh-my-zsh,lesterchan/oh-my-zsh,leafty/oh-my-zsh,xiaogaozi/oh-my-zsh,johnamiahford/oh-my-zsh,tuxlife/oh-my-zsh,eiginn/oh-my-zsh,nunogt/oh-my-zsh,cristianstu/oh-my-zsh,jevinskie/oh-my-zsh,yusiwen/oh-my-zsh,ttelford/oh-my-zsh,nunogt/oh-my-zsh,codingjester/oh-my-zsh,eiginn/oh-my-zsh,erwinvaneijk/oh-my-zsh,bhongy/oh-my-zsh,rxfork/oh-my-zsh,kasyaar/zsh_config,jhannah/oh-my-zsh,bryteise/oh-my-zsh,jhannah/oh-my-zsh,kasyaar/zsh_config,lesterchan/oh-my-zsh,ksaynice/oh-my-zsh,rxfork/oh-my-zsh,data219/oh-my-zsh,jevinskie/oh-my-zsh,tuxlife/oh-my-zsh,stevenspasbo/oh-my-zsh,alperyeg/oh-my-zsh,sankara/oh-my-zsh,yusiwen/oh-my-zsh,matthewberryman/oh-my-zsh,sankara/oh-my-zsh,johnamiahford/oh-my-zsh,bhongy/oh-my-zsh,stevenspasbo/oh-my-zsh,ksaynice/oh-my-zsh,ohlol/oh-my-zsh,ShadowStar/oh-my-zsh,tonydeng/oh-my-zsh,krafczyk/oh-my-zsh,johnamiahford/oh-my-zsh,aaronbieber/oh-my-zsh,ShadowStar/oh-my-zsh,xiaogaozi/oh-my-zsh,hoggarth/oh-my-zsh,alperyeg/oh-my-zsh,ohlol/oh-my-zsh,RavuAlHemio/oh-my-zsh,bryteise/oh-my-zsh,johnamiahford/oh-my-zsh,codingjester/oh-my-zsh,ksaynice/oh-my-zsh