Add external payload size and count to Visibility Schema

[simvlad]

What changed?

Added TemporalExternalPayloadSizeBytes and TemporalExternalPayloadCount to Visibility Schema as pre-defined search attribute.

Why?

We are planning to expose external payload size and count as the search attributes. They are pre-defined, rather than system, because they won't be set on every single workflow, but only ones which store large payloads externally (e.g. in S3).

How did you test it?

• built
• run locally and tested manually
• covered by existing tests
• added new unit test(s)
• added new functional test(s)

Potential risks

Incorrectly modified schema

[rodrigozhou]

You need to update

temporal/schema/embed.go

Line 61 in 95553c7

data, err := assets.ReadFile("elasticsearch/visibility/versioned/v13/index_template_v7.json")

for the tests to pass.