Fix column type after making test more deterministic

Author: craigtaverner

x-pack/plugin/esql/qa/testFixtures/src/main/resources/lookup-join.csv-spec

@@ -252,7 +252,7 @@ FROM employees
 | KEEP emp_no, language_code, language_name, country
 ;
 
-emp_no:integer | language_code:integer | language_name:keyword | country:text
+emp_no:integer | language_code:integer | language_name:keyword | country:keyword
     10091      | 1                     | English               | Canada
     10091      | 1                     | null                  | United Kingdom
     10091      | 1                     | English               | United States of America
@@ -278,7 +278,7 @@ FROM employees
 ;
 
 ignoreOrder:true
-emp_no:integer | language_code:integer | language_name:keyword | country:text
+emp_no:integer | language_code:integer | language_name:keyword | country:keyword
 10001          | 1                     | English               | Canada
 10001          | 1                     | English               | null
 10001          | 1                     | null                  | United Kingdom