fix: instructions to quote filters that include commas (#1794)

## Description

A filter value like `{"user.city": "New York, NY"}` gets interpretted by
Looker as a list of values, and so becomes SQL like
`IN ('New York', 'NY')`. Need to pass a filter value like `{"user.city":
"'New York, NY'"}`.

Add instructions to agents to properly quote filter values that contain
commas.

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🛠️ Fixes #1790

docs/en/resources/tools/looker/looker-query.md

@@ -61,6 +61,8 @@ tools:
           "field.id2": "condition2", ...}. Do not put the field.id in
           quotes. Filter expressions can be found at
           https://cloud.google.com/looker/docs/filter-expressions.
+          If the condition is a string that contains a comma, use a second
+          set of quotes. For example, {"user.city": "'New York, NY'"}.
 
           Sorts can be specified like [ "field.id desc 0" ].
 

internal/prebuiltconfigs/tools/looker.yaml

@@ -118,6 +118,8 @@ tools:
           quotes. Filter expressions can be found at
           https://cloud.google.com/looker/docs/filter-expressions. There
           is one mistake in that, however, Use `not null` instead of `-NULL`.
+          If the condition is a string that contains a comma, use a second
+          set of quotes. For example, {"user.city": "'New York, NY'"}.
 
           Sorts can be specified like [ "field.id desc 0" ].