Fix 4545 Sqlite 3-35 On Conflict

[griffio]

Allow multiple ON CONFLICT clauses that are evaluated in order, The final ON CONFLICT clause may omit the conflict target and yet still use DO UPDATE

fixes #4545

Restrict final ON CONFLICT to have optional conflict target

For example - add a new mix-in to check the new upsertClauseList element to annotate that only the last element is allowed optional conflict target 🎯

The new InsertStmtMixin copies the 3.24 annotations but must now validate more than one ON CONFLICT clause

insert_stmt ::= [ {with_clause} ]
  ( INSERT OR REPLACE | REPLACE | INSERT OR ROLLBACK | INSERT OR ABORT | INSERT OR FAIL | INSERT OR IGNORE | INSERT )
  INTO [ {database_name} DOT ] {table_name} [ AS {table_alias} ]
  [ LP {column_name} ( COMMA {column_name} ) * RP ] {insert_stmt_values} [ ( upsert_clause ) * ] [ returning_clause ] {
  mixin = "app.cash.sqldelight.dialects.sqlite_3_35.grammar.mixins.InsertStmtMixin"
  pin = 5
  override = true
}