removeVault() will block because of incorrect vaults length

[tushargargght]

Describe the bug

In SameAssetUnderlyingsAbstractVault.sol, removeVaults() accepts a vaultIndex to remove the corresponding vault from _activeUnderlyingVaults, and the index is required to be less than the length of _activeUnderlyingVaults.

uint256 newUnderlyingVaultsLen = _activeUnderlyingVaults.length - 1;
require(vaultIndex <= newUnderlyingVaultsLen, "Invalid from vault index");

We also noticed the same vaultIndex is used to get the underlyingVaultIndex from the vaultIndexMap later.

uint256 underlyingVaultIndex = vaultIndexMapMem.map(vaultIndex);

This means if the governor wants to remove the nth vault in the vaultMap, it requires having at least n active vaults. However, this is not always the case, as previously removed vaults will still occupy their indexes on the map, and that will block the governor from removing active vaults. Since there is a limit of total active vaults, the issue will also block the governor from adding new vaults once after adding 15 vaults