feat: Non-zero Default Fees (#9371)

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## Description

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closes: #9106

---

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write a little note why.

- [x] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [ ] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [ ] Wrote unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [ ] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [ ] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
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testutil/network/util.go

@@ -27,6 +27,10 @@ func startInProcess(cfg Config, val *Validator) error {
 	tmCfg := val.Ctx.Config
 	tmCfg.Instrumentation.Prometheus = false
 
+	if err := val.AppConfig.ValidateBasic(); err != nil {
+		return err
+	}
+
 	nodeKey, err := p2p.LoadOrGenNodeKey(tmCfg.NodeKeyFile())
 	if err != nil {
 		return err