For sparklines, check that viz type is line (#17950)

* For sparklines, check that viz type is line

this actually goes to fix waterfalls. They would match these
requirements but the viz type of waterfall would give results that would
dip out of the viewport. Fallback to table rendering

* Prevent waterfall rendering as sparkline

* please run that cancelled test again, GitHub®

src/metabase/pulse/render.clj

@@ -98,7 +98,8 @@
         (and (= @col-sample-count 2)
              (> @row-sample-count 1)
              (types/temporal-field? @col-1)
-             (number-field? @col-2))
+             (number-field? @col-2)
+             (not= display-type :waterfall))
         (chart-type :sparkline "result has 2 cols (%s (temporal) and %s (number)) and > 1 row" (col-description @col-1) (col-description @col-2))
 
         (and (= @col-sample-count 2)