[ES|QL] remove text option from inline casting (elastic#236133)

## Summary

close elastic#198037

Author: drewdaemon

src/platform/packages/shared/kbn-esql-ast/src/definitions/utils/expressions.test.ts

@@ -111,7 +111,6 @@ describe('getExpressionType', () => {
       { expectedType: 'keyword', expression: '1::keyword' },
       { expectedType: 'long', expression: '1::long' },
       { expectedType: 'keyword', expression: '1::string' },
-      { expectedType: 'keyword', expression: '1::text' },
       { expectedType: 'time_duration', expression: '1::time_duration' },
       { expectedType: 'unsigned_long', expression: '1::unsigned_long' },
       { expectedType: 'version', expression: '"1.2.3"::version' },

src/platform/packages/shared/kbn-esql-ast/src/definitions/utils/expressions.ts

@@ -66,8 +66,6 @@ export function getExpressionType(
         return 'boolean';
       case 'string':
         return 'keyword';
-      case 'text':
-        return 'keyword';
       case 'datetime':
         return 'date';
       default: