Add admin key to get /network/nodes endpoint

[sdimitrov9]

Description:
Adding admin_key to the get /network/nodes REST API

Related issue(s):

Fixes #8757

Notes for reviewer:

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.25%. Comparing base (0c38f14) to head (66f2822).
Report is 18 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #9776      +/-   ##
============================================
+ Coverage     92.23%   92.25%   +0.02%     
- Complexity     7628     7769     +141     
============================================
  Files           937      951      +14     
  Lines         32117    32467     +350     
  Branches       4071     4113      +42     
============================================
+ Hits          29622    29953     +331     
- Misses         1542     1546       +4     
- Partials        953      968      +15     

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[SvetBorislavov]

Hey, the 'admin_key' value structure is not correct. The node's admin_key is of type 'Key', here is the definition inside the protobuf: https://github.com/hashgraph/hedera-protobufs/blob/main/services/state/addressbook/node.proto#L148
The mirror node currently returns this kind of 'Key' structure in the following format:

"key": {
        "_type": "ED25519",
        "key": "61f37fc1bbf3ff4453712ee6a305c5c7255955f7889ec3bf30426f1863158ef4"
      }

This is an example of the /accounts response:
Here is the whole request: https://testnet.mirrornode.hedera.com/api/v1/accounts?account.id=2159149

The structure should be such because the key may be a KeyList with multiple levels.

The key type is also shown in the screenshot you have attached.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[steven-sheehy]

The test should populate a valid key

[steven-sheehy]

All specs have the admin_key as null. We should populate valid admin keys for at least one file like this one. It should include different variations like ED25519, ECDSA, 3200 immutable key, and one complex key.