[DistGB]Restore the gb_convert_single_dgl_partition of the public function in partition.py

[CfromBU]

Description

In PR https://github.com/dmlc/dgl/pull/7727 the public function gb_convert_single_dgl_partition was modified and its functionality was replaced by _convert_partition_to_graphbolt. In this PR, _convert_partition_to_graphbolt is renamed to gb_convert_single_dgl_partition to allow other project can use the function normally as before.

This PR can resolve the issue https://github.com/dmlc/dgl/issues/7802.

Changes

Renaming the function _convert_partition_to_graphbolt to gb_convert_single_dgl_partition .
Renaming the function gb_convert_single_dgl_partition to _convert_dgl_partition_to_gb .

[Rhett-Ying]

@CfromBU pls resolve he conflicts first. just rebase on latest DGL master branch

[dgl-bot]

To trigger regression tests:

• @dgl-bot run [instance-type] [which tests] [compare-with-branch];
  For example: @dgl-bot run g4dn.4xlarge all dmlc/master or @dgl-bot run c5.9xlarge kernel,api dmlc/master

[dgl-bot]

Commit ID: 27bb682

Build ID: 1

Status: ⚪️ CI test cancelled due to overrun.

Report path: link

Full logs path: link

[dgl-bot]

Commit ID: 16a606c

Build ID: 2

Status: ✅ CI test succeeded.

Report path: link

Full logs path: link

[Rhett-Ying]

@CfromBU is this PR ready for review? pls fix the lint failure

[dgl-bot]

Commit ID: be716ee

Build ID: 3

Status: ✅ CI test succeeded.

Report path: link

Full logs path: link

[dgl-bot]

Commit ID: 53416c1

Build ID: 4

Status: ✅ CI test succeeded.

Report path: link

Full logs path: link

[Rhett-Ying]

@thvasilo could you help verify it with tomorrow's nightly build?