Describe the bug
While packages/cubejs-client-core/src/time.tstries to customize an internal dayjs instance, these options are also applied to the default dayjs instance.

To Reproduce

import dayjs from 'dayjs';
import { internalDayjs } from '@cubejs-client/core'

console.log(dayjs().startOf('week').format('dddd'); // Sunday

const cubeDayjs = internalDayjs(); // sets weekStart to 1

console.log(dayjs().startOf('week').format('dddd'); // Monday

Expected behavior
Cube Client's dayjs internal instance options should not be reflected in the default dayjs instance.

Version:
"@cubejs-client/core": "^1.5.4",