fix: add constraint and runtime check for provisioner logs size limit (#18893)

This PR sets a constraint of 1MB on the provisioner job logs written to
the database. This is consistent with the constraint we place on
workspace agent logs:
https://github.com/coder/coder/blob/4ac6be6d835dc36c242e35a26b584b784040bf28/coderd/database/dump.sql#L2030

It also adds a message printed to the front end about the provisioner
log overflow, and updates the message printed to the front end when
workspace startup logs exceed the max, as it was causing some customers
to think their startup script had failed to run.

coderd/wsbuilder/wsbuilder.go

@@ -409,6 +409,7 @@ func (b *Builder) buildTx(authFunc func(action policy.Action, object rbac.Object
 			Valid:      true,
 			RawMessage: traceMetadataRaw,
 		},
+		LogsOverflowed: false,
 	})
 	if err != nil {
 		return nil, nil, nil, BuildError{http.StatusInternalServerError, "insert provisioner job", err}