Enable scan in match.

[Shylock-Hg]

What type of PR is this?

• bug
• feature
• enhancement

What problem(s) does this PR solve?

Issue(s) number:

Close #5399 #5170

Description:

Remove limit requirement of scan in match, e.g. we can run match (v) return v directly now.

      """
      MATCH p = shortestPath( (a)-[e*..5]-(b) )
        WHERE id(a) == 'Tim Duncan' OR id(b) in ['Spurs', 'Tony Parker', 'Yao Ming']
        RETURN p
      """

This query failed in CI, but can't reproduce even in vesoft/nebula-dev:centos7 docker environment. And not caused by ScanVertices so skip it now. Could see detail of this in #5428

How do you solve it?

Special notes for your reviewer, ex. impact of this fix, design document, etc:

Checklist:

Tests:

• Unit test(positive and negative cases)
• Function test
• Performance test
• N/A

Affects:

• Documentation affected (Please add the label if documentation needs to be modified.)
• Incompatibility (If it breaks the compatibility, please describe it and add the label.）
• If it's needed to cherry-pick (If cherry-pick to some branches is required, please label the destination version(s).)
• Performance impacted: Consumes more CPU/Memory

Release notes:

Please confirm whether to be reflected in release notes and how to describe:

ex. Fixed the bug .....

[codesigner]

LGTM

[yixinglu]

why to change this field to optional? The original implementation seems OK.

[Shylock-Hg]

When |a| join |a| will lead to error.

[wey-gu]

In documentation, we could remove the hacky query example as this issue mentioned also.

#5436

cc @cooper-lzy @abby-cyber

[abby-cyber]

vesoft-inc/nebula-docs-cn#2705