Update tests for interop cross chain updates

[sitetester]

What was the problem?

This PR resolves #8193

How was it solved?

How was it tested?

• Since we have a separate verifyRoutingRules method, relevant tests moved to a separate describe('verifyRoutingRules')
• Repeated expects relevant to CCMProcessedCode.INVALID_CCM_ROUTING_EXCEPTION are now called once

[codecov]

Codecov Report

Merging #9138 (28ec134) into release/6.1.0 (799585e) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@                Coverage Diff                @@
##           release/6.1.0    #9138      +/-   ##
=================================================
- Coverage          84.35%   84.35%   -0.01%     
=================================================
  Files                655      655              
  Lines              24113    24113              
  Branches            3497     3497              
=================================================
- Hits               20341    20340       -1     
- Misses              3772     3773       +1     

Files	Coverage Δ
...nteroperability/base_cross_chain_update_command.ts	97.71% <ø> (ø)
...in/commands/submit_mainchain_cross_chain_update.ts	98.76% <100.00%> (ø)
...in/commands/submit_sidechain_cross_chain_update.ts	96.29% <100.00%> (ø)

... and 1 file with indirect coverage changes

[AndreasKendziorra]

I didn't check yet if all point reported in the issue were addressed.

[ishantiw]

Apart from @AndreasKendziorra comment, a minor comment, else looks good to me