remove kovan debug node

libs/remix-debug/src/init.ts

@@ -22,8 +22,7 @@ export function web3DebugNode (network) {
     Main: 'https://rpc.archivenode.io/e50zmkroshle2e2e50zm0044i7ao04ym',
     Rinkeby: 'https://remix-rinkeby.ethdevops.io',
     Ropsten: 'https://remix-ropsten.ethdevops.io',
-    Goerli: 'https://remix-goerli.ethdevops.io',
-    Kovan: 'https://remix-kovan.ethdevops.io'
+    Goerli: 'https://remix-goerli.ethdevops.io'
   }
   if (web3DebugNodes[network]) {
     return loadWeb3(web3DebugNodes[network])

libs/remix-lib/src/init.ts

@@ -21,8 +21,7 @@ export function web3DebugNode (network) {
     Main: 'https://gethmainnet.komputing.org',
     Rinkeby: 'https://remix-rinkeby.ethdevops.io',
     Ropsten: 'https://remix-ropsten.ethdevops.io',
-    Goerli: 'https://remix-goerli.ethdevops.io',
-    Kovan: 'https://remix-kovan.ethdevops.io'
+    Goerli: 'https://remix-goerli.ethdevops.io'
   }
   if (web3DebugNodes[network]) {
     return this.loadWeb3(web3DebugNodes[network])

libs/remix-ui/debugger-ui/src/lib/debugger-ui.tsx

@@ -282,7 +282,7 @@ export const DebuggerUI = (props: DebuggerUIProps) => {
             }} type="checkbox" title="Debug with generated sources" />
             <label data-id="debugGeneratedSourcesLabel" className="form-check-label custom-control-label" htmlFor="debugGeneratedSourcesInput">Use generated sources (from Solidity v0.7.2)</label>
           </div>
-          { (state.validationError && !state.txNumberIsEmpty) && <span className="w-100 py-1 text-danger validationError">{state.validationError}</span> }
+          { state.validationError && <span className="w-100 py-1 text-danger validationError">{state.validationError}</span> }
         </div>
         <TxBrowser requestDebug={ requestDebug } unloadRequested={ unloadRequested } updateTxNumberFlag={ updateTxNumberFlag } transactionNumber={ state.txNumber } debugging={ state.debugging } />
         { state.debugging && <StepManager stepManager={ stepManager } /> }