Add support for multiple on-conflict clauses in inserts on SQLite

Add support for multiple on-conflict clauses in inserts on SQLite

Multiple on-conflict clauses support for SQLite

Fixes: #13113
### Description
Follows up to [#13113](https://github.com/sqlalchemy/sqlalchemy/issues/13113)
Add support for multiple on-conflict clauses in insert statements for SQLite database
As [CaselIT](https://github.com/CaselIT) proposed, this required a small change in `apply_to_insert()` function. I've replaced `self.append_replacing_same_type` to `lambda ex: [*ex, self]` and removed `@_on_conflict_exclusive` from `on_conflict_do_update()` and `on_conflict_do_nothing()` methods

This pull request is:
- [ ] A new feature implementation
    - Tests included

**Have a nice day!**

Closes: #13457
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/13457
Pull-request-sha: 356885a839850344cfdc0818b1d6bb64ee61c417

Change-Id: I4e184c4e57018048f97b9f7ff30deded6d9f1a9e