imp(dymns): persist EIP-155 part only, for RollApp-related configs, to avoid migration when RollApp chain-id changed

[VictorTrustyDev]

Description

---

Closes #1078

To avoid data migration when a RollApp chain-id changed due to fraud,... x/dymns now adjust logic to save only EIP-155 part (ra_100-1 => 100) instead of Full chain-id.

This PR contains:

• Persist only EIP-155 part for Dym-Name config if the chain is a RollApp.
  • Adjustment to the ChainID field of Dym-Name config.
• Persist only EIP-155 part for Alias <=> RollApp linking.
  • Adjustment to the underlying store value, now EIP-155 instead of Full chain-id.
• Improve performance by adding 2 methods into x/rollapp keeper:
  • IsRollAppExists(string) bool
  • GetRollAppIdByEIP155(string) string
• Add data migration for Playground-only.

cc: @omritoptix @danwt

---

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow-up issues.

PR review checkboxes:

I have...

• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Targeted PR against the correct branch
• included the correct type prefix in the PR title
• Linked to the GitHub issue with discussion and accepted design
• Targets only one GitHub issue
• Wrote unit and integration tests
• Wrote relevant migration scripts if necessary
• All CI checks have passed
• Added relevant godoc comments
• Updated the scripts for local run, e.g genesis_config_commands.sh if the PR changes parameters
• Add an issue in the e2e-tests repo if necessary

SDK Checklist

• Import/Export Genesis
• Registered Invariants
• Registered Events
• Updated openapi.yaml
• No usage of go map
• No usage of time.Now()
• Used fixed point arithmetic and not float arithmetic
• Avoid panicking in Begin/End block as much as possible
• No unexpected math Overflow
• Used sendCoin and not SendCoins
• Out-of-block compute is bounded
• No serialized ID at the end of store keys
• UInt to byte conversion should use BigEndian

Full security checklist here

---

For Reviewer:

• Confirmed the correct type prefix in the PR title
• Reviewers assigned
• Confirmed all author checklist items have been addressed

---

After reviewer approval:

• In case the PR targets the main branch, PR should not be squash merge in order to keep meaningful git history.
• In case the PR targets a release branch, PR must be rebased.

[VictorTrustyDev]

No need for now.