Problem: method eth_chainId crashed occasionally

[mmsqe]

add fallback default config to ensure no panic in IsEIP155 check

Closes: #515

Description

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For contributor use:

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

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For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[codecov]

Codecov Report

Attention: Patch coverage is 26.58228% with 116 lines in your changes missing coverage. Please review.

Project coverage is 60.59%. Comparing base (d26adad) to head (c454808).
Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
rpc/types/utils.go	0.00%	29 Missing ⚠️
types/int.go	5.00%	19 Missing ⚠️
rpc/backend/tx_info.go	44.82%	10 Missing and 6 partials ⚠️
x/evm/types/key.go	0.00%	16 Missing ⚠️
x/evm/keeper/grpc_query.go	22.22%	5 Missing and 2 partials ⚠️
rpc/backend/blocks.go	53.84%	3 Missing and 3 partials ⚠️
rpc/backend/utils.go	28.57%	4 Missing and 1 partial ⚠️
indexer/kv_indexer.go	50.00%	2 Missing and 2 partials ⚠️
rpc/backend/node_info.go	50.00%	2 Missing and 2 partials ⚠️
rpc/stream/rpc.go	0.00%	4 Missing ⚠️
... and 3 more

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #516      +/-   ##
===========================================
- Coverage    61.13%   60.59%   -0.55%     
===========================================
  Files          128      128              
  Lines         9607     9724     +117     
===========================================
+ Hits          5873     5892      +19     
- Misses        3174     3255      +81     
- Partials       560      577      +17     

Files with missing lines	Coverage Δ
rpc/backend/chain_info.go	77.77% <60.00%> (ø)
rpc/types/events.go	68.42% <50.00%> (-0.95%)	⬇️
x/evm/keeper/config.go	91.30% <66.66%> (-2.45%)	⬇️
indexer/kv_indexer.go	66.66% <50.00%> (-1.67%)	⬇️
rpc/backend/node_info.go	46.74% <50.00%> (-0.50%)	⬇️
rpc/stream/rpc.go	0.00% <0.00%> (ø)
rpc/backend/utils.go	47.87% <28.57%> (-0.88%)	⬇️
rpc/backend/blocks.go	84.11% <53.84%> (-1.71%)	⬇️
x/evm/keeper/grpc_query.go	77.67% <22.22%> (-0.89%)	⬇️
rpc/backend/tx_info.go	59.92% <44.82%> (-2.63%)	⬇️
... and 3 more