Remove unnecessary copy in Eth1DataHasEnoughSupport (#16118)

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**What type of PR is this?**

Other

**What does this PR do? Why is it needed?**

- Remove unnecessary `Copy()` call in `Eth1DataHasEnoughSupport`
- `data.Copy()` was called on every iteration of the vote counting loop,
even though `AreEth1DataEqual` only reads the data and never mutates it.
- Additionally, `Eth1DataVotes()` already returns copies of all votes,
so state is protected regardless.

**Which issues(s) does this PR fix?**

Fixes #

**Other notes for review**

**Acknowledgements**

- [x] I have read
[CONTRIBUTING.md](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md).
- [x] I have included a uniquely named [changelog fragment
file](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md#maintaining-changelogmd).
- [x] I have added a description to this PR with sufficient context for
reviewers to understand this PR.

Author: satushh

beacon-chain/core/blocks/eth1_data.go

@@ -60,7 +60,7 @@ func Eth1DataHasEnoughSupport(beaconState state.ReadOnlyBeaconState, data *ethpb
 	voteCount := uint64(0)
 
 	for _, vote := range beaconState.Eth1DataVotes() {
-		if AreEth1DataEqual(vote, data.Copy()) {
+		if AreEth1DataEqual(vote, data) {
 			voteCount++
 		}
 	}

changelog/satushh-eth1copy.md

@@ -0,0 +1,3 @@
+### Removed
+
+- Unnecessary copy is removed from Eth1DataHasEnoughSupport