fix(query): delete len check in mget_database/table_names_by_ids

[TCeason]

I hereby agree to the terms of the CLA available at: https://docs.databend.com/dev/policies/cla/

Summary

delete some err check

• Fixes #[Link the issue here]

Tests

• Unit Test
• Logic Test
• Benchmark Test
• No Test - Explain why

Type of change

• Bug Fix (non-breaking change which fixes an issue)
• New Feature (non-breaking change which adds functionality)
• Breaking Change (fix or feature that could cause existing functionality not to work as expected)
• Documentation Update
• Refactoring
• Performance Improvement
• Other (please describe):

---

This change is 

[github-actions]

Docker Image for PR

• tag: pr-15640-49fa839

note: this image tag is only available for internal use,
please check the internal doc for more details.

[TCeason]

In dev warehouse system:

deploy@(system)/default> show grants;
error: APIError: ResponseError with 2001: fail to mget_table_names_by_ids: , source: The system is experiencing high load, please retry later

In test warehouse show_grants it fixed:

deploy@(show_grants)/default> select version();

SELECT
  version()

┌────────────────────────────────────────────────────────────────────────────────────────────────┐
│                                            version()                                           │
│                                             String                                             │
├────────────────────────────────────────────────────────────────────────────────────────────────┤
│ Databend Query v1.2.490-nightly-49fa83976d(rust-1.78.0-nightly-2024-05-25T11:22:38.392488593Z) │
└────────────────────────────────────────────────────────────────────────────────────────────────┘
1 row read in 1.515 sec. Processed 1 row, 1B (0.66 row/s, 0B/s)

deploy@(show_grants)/default> show grants;

SHOW GRANTS

┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ privileges │     object_name    │     object_id    │ grant_to │  name  │                            grants                           │
│   String   │       String       │ Nullable(UInt64) │  String  │ String │                       Nullable(String)                      │
├────────────┼────────────────────┼──────────────────┼──────────┼────────┼─────────────────────────────────────────────────────────────┤
│ ALL        │ *.*                │             NULL │ USER     │ deploy │ GRANT ALL ON *.* TO 'deploy'@'%'                            │
│ ·          │ ·                  │                · │ ·        │ ·      │ ·                                                           │
│ ·          │ ·                  │                · │ ·        │ ·      │ ·                                                           │
│ ·          │ ·                  │                · │ ·        │ ·      │ ·                                                           │
xxx                 │                  │          │        │                                                             │
│ (2 shown)  │                    │                  │          │        │                                                             │
└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
31 rows read in 1.387 sec. Processed 31 rows, 4.52 KiB (22.36 rows/s, 3.26 KiB/s)

[drmingdrmer]

Reviewed 1 of 2 files at r1, 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @TCeason)