### Description

Only "search hits" based queries (no aggregations) provide a consistent view on the data when paginating through the result set. With point-in-time, it is possible to support transactional semantics for aggregation queries as well.

This issue is somewhat blocked by https://github.com/elastic/elasticsearch/issues/75528 because a PIT can not immediately be closed if the aggregation result set contains less than `fetch_size` records. This could cause some increased resource utilization due to open PITs. Especially if the client does not close the SQL cursor.
x-pack/plugin/sql/qa/server/src/main/java/org/elasticsearch/xpack/sql/qa/rest/RestSqlTestCase.java
String cursor = null;
        for (int i = 0; i < count; i += 2) {
            Map<String, Object> response;
            if (i == 0) {
                response = runSql(new StringEntity(sqlRequest, ContentType.APPLICATION_JSON), "", mode);
            } else {
                columnar = randomBoolean();
                response = runSql(
                    new StringEntity(cursor(cursor).mode(mode).columnar(columnarValue(columnar)).toString(), ContentType.APPLICATION_JSON),
                    StringUtils.EMPTY,
                    mode
                );
            }
            Map<String, Object> expected = new HashMap<>();
            if (i == 0) {
                expected.put(
                    "columns",
                    Arrays.asList(
                        columnInfo(mode, "text", "text", JDBCType.VARCHAR, Integer.MAX_VALUE),
                        columnInfo(mode, "number", "long", JDBCType.BIGINT, 20),
                        columnInfo(mode, "s", "double", JDBCType.DOUBLE, 25),
                        columnInfo(mode, "SCORE()", "float", JDBCType.REAL, 15)
                    )
                );
            }
            if (columnar) {
                expected.put(
                    "values",
                    Arrays.asList(
                        Arrays.asList("text" + i, "text" + (i + 1)),