BigQuery doesn't work with the --interactive option enabled

[vvkh]

Describe the bug
If the --interactive option is enabled, data-diff uses EXPLAIN keyword in the queries which is not supported by BigQuery.

Make sure to include the following (minus sensitive information):

╰─# data-diff --verbose --json --interactive bigquery://.../... <table1> <table2> -k <column1> -k <column 2> -w "<filter expression>"
15:28:35 DEBUG    Running SQL (BigQuery): SELECT ...                                                    
         DEBUG    Running SQL (BigQuery): SELECT ...                                                
15:28:36 DEBUG    [BigQuery] Schema = ...                                                                                                                                                  
         INFO     Diffing schemas...                                                                                                                                                  __main__.py:77
         INFO     Diffing using columns: key=('<column1>', '<column2>') update=None extra=().                                                                      __main__.py:496
         INFO     Using algorithm 'joindiff'.                                                                                                                                        __main__.py:497
         DEBUG    Running SQL (BigQuery): SELECT TRIM(`<column2>`) FROM `...`.`...`.`<table1>` WHERE (<filter expression>) LIMIT 64                                                                                                                                                      
         ERROR    Exception when trying to execute SQL code:                                                                                                                         __main__.py:327
                      EXPLAIN SELECT TRIM(`<column2>`) FROM `...`.`...`.`<table1>` WHERE (<filter expression>)) LIMIT 64                                                                                                                                                                    
                                                                                                                                                                                                    
                  Got error: 400 Statement not supported: ExplainStatement at [1:1]