Andrew7234/add validator names

[Andrew7234]

Per request from explorer folks, we now include the validator human-readable name in /*delegations* endpoints when available. Note that the e2e test updates do not reflect this change because the metadata_registry analyzer isn't enabled for e2e_regression tests. However, I did enable it manually and found a couple outdated tests which are also fixed in this PR.

[ptrus]

The API's approach to handling validator metadata has become somewhat inconsistent.

Currently, we return validator_name for these endpoints, EntityInfo for block proposers and signers, and ValidatorMedia for validator-specific endpoints. Although these represent the same underlying data, the choice of response fields across different endpoints feels somewhat arbitrary.

To improve this, I suggest either:

1. Unify the responses so all relevant endpoints return the same metadata structure, or
2. (my preference, but apparently not the forntend's): Keep metadata to be returned only by the validator endpoint. The frontend can cache and reuse this information across different parts of the app - whenever dealing with consensus addresses.

---

Main Reasoning for Option 2:

• Imagine a design choice is make to also display validator logo next to the name when showing delegations - this would mean updating these endpoints by also including validator_logo
• If a delegator is a validator, the frontend would likely also want to show the validator name. With the current approach, we'd need to introduce additional fields like delegator_name to the delegation endpoint
• Consider other endpoints, like consensus/account/{address}. When querying account information for a validator, the frontend would want to show the validator's name. Following the current setup, this would mean adding ValidatorMedia to the account endpoint response.
• Similarly, if a consensus transaction was submitted by an address that belongs to a validator (or if the recipient is a validator), the frontend would likely want to display the validator's name. This would mean adding the validator metadata to yet more endpoints (consensus/transactions), resulting in more redundancy.

[buberdds]

(my preference, but apparently not the forntend's): Keep metadata to be returned only by the validator endpoint.

We have discussed this in https://app.clickup.com/t/869683ayv and I was under the impression that we agreed to handle this on the frontend (PR was created last week oasisprotocol/explorer#1576), since we need the names to be displayed in multiple views.