Fix conductor testing race condition

[devyetii]

Fixes

Related discussion: https://0chain.slack.com/archives/C01GMABG2T1/p1695094338460679

Changes

• Added RWMutex and used anywhere nodes map is used
• Removed special handling of validator/blobber in Server.State since cannot be useful.

Need to be mentioned in CHANGELOG.md?

Tests

Tasks to complete before merging PR:

• Ensure system tests are passing. If not Run them manually to check for any regressions 📋
• Do any new system tests need added to test this change? do any existing system tests need updated? If so create a PR at 0chain/system_test
• Merge your system tests PR to master AFTER merging this PR

Associated PRs (Link as appropriate):

• blobber:
• gosdk:
• system_test:
• zboxcli:
• zwalletcli:
• Other: ...

[codecov-commenter]

Codecov Report

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@@              Coverage Diff               @@
##             sprint-1.11    #2793   +/-   ##
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  Misses                 ?    44782           
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Flag	Coverage Δ
Unit-Tests	28.62% <0.00%> (?)

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