fix: return error when single node is not found in static topology

[ZuLiangWang]

Rationale

Fix return error when single node is not found in static topology, make it is possible to assign shards to nodes when a single node is not found.

Detailed Changes

Just continue instead of return error when single node is not found in static topology.

Test Plan

Pass all unit tests and integration test.

[codecov[bot]]

Codecov Report

Merging #226 (ea360ad) into main (7f1354e) will increase coverage by 21.40%. Report is 55 commits behind head on main. The diff coverage is 65.25%.

:exclamation: Current head ea360ad differs from pull request most recent head 0766a11. Consider uploading reports for the commit 0766a11 to get more accurate results

@@             Coverage Diff             @@
##             main     #226       +/-   ##
===========================================
+ Coverage   39.66%   61.07%   +21.40%     
===========================================
  Files          34       43        +9     
  Lines        4213     5338     +1125     
===========================================
+ Hits         1671     3260     +1589     
+ Misses       2317     1676      -641     
- Partials      225      402      +177     

Files	Coverage Δ
pkg/coderr/code.go	0.00% <ø> (ø)
server/cluster/cluster.go	50.00% <100.00%> (ø)
server/cluster/metadata/topology_manager.go	75.63% <100.00%> (+75.63%)	:arrow_up:
.../coordinator/procedure/ddl/droptable/drop_table.go	48.22% <100.00%> (+1.51%)	:arrow_up:
server/coordinator/procedure/util.go	0.00% <ø> (ø)
server/storage/meta.go	0.00% <ø> (ø)
server/cluster/metadata/table_manager.go	67.00% <80.00%> (+67.00%)	:arrow_up:
...rdinator/procedure/ddl/createtable/create_table.go	50.38% <85.71%> (+2.42%)	:arrow_up:
server/coordinator/watch/watch.go	55.14% <83.33%> (+0.42%)	:arrow_up:
server/id/id_impl.go	63.73% <75.00%> (ø)
... and 21 more

... and 1 file with indirect coverage changes

[ShiKaiWi]

@ZuLiangWang Let's make a rebase to resolve the conflicts.