[Enhancement] Add current_date as default value function for starrocks

[rohitrs1983]

Why I'm doing:

What I'm doing:

Add current_date as default value function for starrocks

MySQL [test]> CREATE TABLE IF NOT EXISTS test_date (k TINYINT, v1 DATE NOT NULL DEFAULT CURRENT_DATE, v2 INT) UNIQUE KEY(K) DISTRIBUTED BY HASH(k) PROPERTIES("replication_num" = "1");
Query OK, 0 rows affected (0.046 sec)

MySQL [test]> insert into test_date(k,v2) values(1,2);
Query OK, 1 row affected (0.488 sec)
{'label':'insert_59dfb5d5-675c-11ef-9627-02420a1fd64c', 'status':'VISIBLE', 'txnId':'7016'}

MySQL [test]> select * from test_date;
+------+------------------+------+
| k    | v1                 | v2   |
+------+------------------+------+
|    1 | 2024-08-31 |    2 |
+------+------------------+------+
1 row in set (0.014 sec)

Fixes #50509

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• Interface/UI changes: syntax, type conversion, expression evaluation, display information
• Parameter changes: default values, similar parameters but with different default values
• Policy changes: use new policy to replace old one, functionality automatically enabled
• Feature removed
• Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• I have added test cases for my bug fix or my new feature
• This pr needs user documentation (for new or modified features or behaviors)
  • I have added documentation for my new feature or new function
• This is a backport pr

Bugfix cherry-pick branch check:

• I have checked the version labels which the pr will be auto-backported to the target branch
  • 3.3
  • 3.2
  • 3.1
  • 3.0
  • 2.5

[sonarcloud]

Quality Gate passed

Issues
8 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[github-actions]

[BE Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[Java-Extensions Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[FE Incremental Coverage Report]

❌ fail : 3 / 4 (75.00%)

file detail

	path	covered_line	new_line	coverage	not_covered_line_detail
🔵	com/starrocks/sql/ast/ColumnDef.java	2	3	66.67%	[492]
🔵	com/starrocks/catalog/DefaultExpr.java	1	1	100.00%	[]