No, of course section 8 doesn't say it. Section 10(c) does:

The Legislature may amend or repeal referendum statutes. It may amend or repeal an initiative statute by another statute that becomes effective only when approved by the electors unless the initiative statute permits amendment or repeal without their approval.

Prop 22 was an initiative statute, and it doesn't explicitly permit the legislature to amend or repeal it, so it can't be amended or repealed without the approval of the electors.