fix(eap): speed up GetTrace endpoint pagination (#7614)

Product team reports pagination to be slow, and we think making the
order by clause of the query match the sort key of the CH table will
help (consequently we change the pagination to match the order by). This
is related to the pre-existing bug uncovered as part of
#7586

We will be measuring the speed up by using our internal DD metrics

rollout plan:
- monitor error count via DD:
https://app.datadoghq.com/s/FH6-Y3/vet-mu7-eq2
- monitor sentry issues
- if things go wrong, click revert

---------

Co-authored-by: Rachel Chen <[email protected]>
Co-authored-by: Rachel Chen <[email protected]>

Author: 3 people

snuba/web/rpc/v1/endpoint_export_trace_items.py

@@ -81,7 +81,7 @@ def from_protobuf(cls, page_token: PageToken) -> Optional["ExportTraceItemsPageT
             filters[1].comparison_filter.key.name == "last_seen_timestamp"
             and filters[1].comparison_filter.key.type == AttributeKey.Type.TYPE_DOUBLE
         ):
-            raise ValueError("Invalid page token")
+            raise ValueError("Invalid timestamp")
         last_seen_timestamp = filters[1].comparison_filter.value.val_double
 
         if not (
@@ -95,7 +95,7 @@ def from_protobuf(cls, page_token: PageToken) -> Optional["ExportTraceItemsPageT
             filters[3].comparison_filter.key.name == "last_seen_item_id"
             and filters[3].comparison_filter.key.type == AttributeKey.Type.TYPE_STRING
         ):
-            raise ValueError("Invalid page token")
+            raise ValueError("Invalid item id")
         last_seen_item_id = filters[3].comparison_filter.value.val_str
 
         return cls(