ESQL Union-types missing support for multi-type rename and keep/drop

[craigtaverner]

The following tests fail in the current union-types support, and have been removed pending a fix:

multiIndexMultiColumnTypesRenameAndKeep
required_capability: union_types
required_capability: metadata_fields

FROM sample_data* METADATA _index
| WHERE event_duration > 8000000
| EVAL ts = TO_DATETIME(@timestamp), ts_str = TO_STRING(@timestamp), ts_l = TO_LONG(@timestamp), ip = TO_IP(client_ip), ip_str = TO_STRING(client_ip) 
| KEEP _index, ts, ts_str, ts_l, ip, ip_str, event_duration
| SORT _index ASC, ts DESC
;

_index:keyword      | ts:date                   | ts_str:keyword            | ts_l:long      |  ip:ip         |  ip_str:k      |  event_duration:long
sample_data         | 2023-10-23T13:52:55.015Z  | 2023-10-23T13:52:55.015Z  | 1698069175015  |  172.21.3.15   |  172.21.3.15   |  8268153
sample_data_str     | 2023-10-23T13:52:55.015Z  | 2023-10-23T13:52:55.015Z  | 1698069175015  |  172.21.3.15   |  172.21.3.15   |  8268153
sample_data_ts_long | 2023-10-23T13:52:55.015Z  | 1698069175015             | 1698069175015  |  172.21.3.15   |  172.21.3.15   |  8268153
;

multiIndexMultiColumnTypesRenameAndDrop
required_capability: union_types
required_capability: metadata_fields

FROM sample_data* METADATA _index
| WHERE event_duration > 8000000
| EVAL ts = TO_DATETIME(@timestamp), ts_str = TO_STRING(@timestamp), ts_l = TO_LONG(@timestamp), ip = TO_IP(client_ip), ip_str = TO_STRING(client_ip) 
| DROP @timestamp, client_ip, message
| SORT _index ASC, ts DESC
;

event_duration:long | _index:keyword      | ts:date                   | ts_str:keyword            | ts_l:long      |  ip:ip         |  ip_str:k  
8268153             | sample_data         | 2023-10-23T13:52:55.015Z  | 2023-10-23T13:52:55.015Z  | 1698069175015  |  172.21.3.15   |  172.21.3.15
8268153             | sample_data_str     | 2023-10-23T13:52:55.015Z  | 2023-10-23T13:52:55.015Z  | 1698069175015  |  172.21.3.15   |  172.21.3.15
8268153             | sample_data_ts_long | 2023-10-23T13:52:55.015Z  | 1698069175015             | 1698069175015  |  172.21.3.15   |  172.21.3.15
;

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[craigtaverner]

One attempt to use synthetic attributes to fix this failed because physical planning remove the columns before they could be used. This could be a similar issue to #105821

[craigtaverner]

One of the more recent fixes appears to have fixed this issue, and these tests were already added in the PR at #110476