Merge bitcoin#30962: validation: Disable CheckForkWarningConditions for background chainstate

c0a0c72 validation: Disable CheckForkWarningConditions for background chainstate (Martin Zumsande)

Pull request description:

  The comparison of `m_best_invalid` with the tip of the chainstate makes no sense for the background chainstate and can lead to incorrect log messages.

  Fixes bitcoin#30958

ACKs for top commit:
  fjahr:
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  achow101:
    ACK c0a0c72
  TheCharlatan:
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  tdb3:
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Tree-SHA512: 316811b1ade8521681f3a105c7db59dfdb27b1e13efeba95cd6183d750db2e07f48968e8fc54fe3834d3311519cf8c6b77d7e0fd61facbf2b07598e79110ff85

Author: achow101

src/validation.cpp

@@ -2020,7 +2020,8 @@ void Chainstate::CheckForkWarningConditions()
 
     // Before we get past initial download, we cannot reliably alert about forks
     // (we assume we don't get stuck on a fork before finishing our initial sync)
-    if (m_chainman.IsInitialBlockDownload()) {
+    // Also not applicable to the background chainstate
+    if (m_chainman.IsInitialBlockDownload() || this->GetRole() == ChainstateRole::BACKGROUND) {
         return;
     }