package.json: always call yarn and not npm

packages/app-shell/package.json

packages/common/package.json

packages/data-table-view/package.json

packages/file-handling/package.json

packages/knowledge-base-web-page-element-view/package.json

packages/language-select/package.json

packages/matomo/package.json

packages/notification/package.json

packages/person-profile/package.json

packages/person-select/package.json

packages/provider/package.json

packages/qr-code-scanner/package.json

packages/resource-select/package.json

packages/theme-switcher/package.json

packages/tooltip/package.json