Revert "Add MV_CONTAINS function (elastic#133099)"

This reverts commit 1e58428.

Author: DaveCTurner

docs/changelog/133099.yaml

@@ -1,7 +1,6 @@
 * [`MV_APPEND`](../../functions-operators/mv-functions.md#esql-mv_append)
 * [`MV_AVG`](../../functions-operators/mv-functions.md#esql-mv_avg)
 * [`MV_CONCAT`](../../functions-operators/mv-functions.md#esql-mv_concat)
-* [preview] [`MV_CONTAINS`](../../functions-operators/mv-functions.md#esql-mv_contains)
 * [`MV_COUNT`](../../functions-operators/mv-functions.md#esql-mv_count)
 * [`MV_DEDUPE`](../../functions-operators/mv-functions.md#esql-mv_dedupe)
 * [`MV_FIRST`](../../functions-operators/mv-functions.md#esql-mv_first)

docs/reference/query-languages/esql/_snippets/functions/description/mv_contains.md

@@ -21,9 +21,6 @@ mapped_pages:
 :::{include} ../_snippets/functions/layout/mv_concat.md
 :::
 
-:::{include} ../_snippets/functions/layout/mv_contains.md
-:::
-
 :::{include} ../_snippets/functions/layout/mv_count.md
 :::