feat: add default message tag

[hansieodendaal]

Description

Add a default message tag to FinalSendMessageParams. This enables the tracing of ping-pong and other messages across nodes.

Motivation and Context

• We have a related issue with ping-pong, see [base node] server stops sending pings after being banned for a while #6356. This tracing will assist in analysing the issue.
• With transaction testing, we noticed that some messages have a zero tag; this will also help that tracing.

How Has This Been Tested?

System-level tests.

What process can a PR reviewer use to test or verify this change?

Review code.

Breaking Changes

• None
• Requires data directory on base node to be deleted
• Requires hard fork
• Other - Please specify

[github-actions]

Test Results (CI)

    3 files    120 suites   35m 31s ⏱️
1 275 tests 1 275 ✅ 0 💤 0 ❌
3 817 runs  3 817 ✅ 0 💤 0 ❌

Results for commit df6affb.

[github-actions]

Test Results (Integration tests)

 2 files  + 2  11 suites  +11   31m 31s ⏱️ + 31m 31s
33 tests +33  31 ✅ +31  0 💤 ±0  2 ❌ +2 
36 runs  +36  33 ✅ +33  0 💤 ±0  3 ❌ +3 

For more details on these failures, see this check.

Results for commit df6affb. ± Comparison against base commit bc2ac4c.