Allow EVAL_RO and EVALSHA_RO to be routed to read replica

[zakaf]

Pull Request check-list

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Description of change

• fixes EVAL_RO, EVALSHA_RO doesn't get routed to replicas #2490 by adding EVAL_RO and EVALSHA_RO to READ_COMMANDS
• minor typo fix (Lue -> Lua)
• test_reading_from_replicas_in_round_robin asserts multiple GET commands getting routed to master and replica
  • two READONLY calls would only happen with 3 or more GET commands only if there are two nodes for the slot

In addition, i've tested locally using the below method

1. running MONITOR command on both the master and the replica node
2. RUN EVAL_RO and EVALSHA_RO multiple times
3. see the output of MONITOR to confirm that commands were routed in a round-robin manner

[codecov-commenter]

Codecov Report

Base: 92.22% // Head: 92.22% // Decreases project coverage by -0.00% ⚠️

Coverage data is based on head (a184119) compared to base (55298e4).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2494      +/-   ##
==========================================
- Coverage   92.22%   92.22%   -0.01%     
==========================================
  Files         113      113              
  Lines       29380    29378       -2     
==========================================
- Hits        27096    27094       -2     
  Misses       2284     2284              

Impacted Files	Coverage Δ
redis/commands/cluster.py	94.02% <ø> (ø)
redis/commands/core.py	82.16% <ø> (ø)
tests/test_scripting.py	93.58% <ø> (-0.09%)	⬇️
tests/test_cluster.py	97.01% <100.00%> (ø)

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[zakaf]

@chayim i've created a PR to address #2494. If you have any concern with the PR, please let me know