Get rid of tippy warnings

[pascalwengerter]

Steps to reproduce

1. Run the latest web master
2. Login as any user
3. See browser console

Expected behaviour

No tippy warning

Actual behaviour

Tippy warning as shown below

Screenshots

[pascalwengerter]

In OcDrop.vue, we call destroy on mount (to make sure we only have one instance visible, I assume), which may cause the error. Perhaps we should check for its presence before calling destroy?

  beforeDestroy() {
    destroy(this.tippy)
  },
  mounted() {
    destroy(this.tippy)