chore: Revisit and fix failing examples

[0xivanov]

Description: Revisit and fix failing examples.

This PR fixes:

1. PrngTransaction
2. Client's default localhost mirror node address
3. Adds topic subscribe tests to the CI
4. Adds the examples to the CI

Related issue(s):

Fixes #949

Notes for reviewer:

Checklist

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

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 73.31%. Comparing base (40fa382) to head (ff39d67).

Files	Patch %	Lines
prng_transaction.go	0.00%	2 Missing :warning:
client.go	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #973 +/- ## ========================================== + Coverage 72.71% 73.31% +0.59% ========================================== Files 166 166 Lines 23349 23351 +2 ========================================== + Hits 16979 17119 +140 + Misses 5690 5549 -141 - Partials 680 683 +3 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[sonarcloud[bot]]

Quality Gate passed

Issues
3 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 SonarCloud