Fix greedy_best_first (#8775)

* fix: typo
#8770

* refactor: delete unnecessary continue

* add test grids

* fix: add \_\_eq\_\_ in Node class
#8770

* fix: delete unnecessary code
- node in self.open_nodes is always better node
#8770

* fix: docstring

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* fix: docstring max length

* refactor: get the successors using a list comprehension

* Apply suggestions from code review

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Tianyi Zheng <tianyizheng02@gmail.com>