fix: do not require connection encrypters (#1752)

Because we now have transports that do their own encryption (e.g.
webrtc, webtransport) do not require additional connection encrypters
to be configured.

src/config.ts

@@ -34,10 +34,6 @@ export function validateConfig <T extends ServiceMap = Record<string, unknown>>
     throw new CodeError(messages.ERR_TRANSPORTS_REQUIRED, codes.ERR_TRANSPORTS_REQUIRED)
   }
 
-  if (resultingOptions.connectionEncryption == null || resultingOptions.connectionEncryption.length === 0) {
-    throw new CodeError(messages.CONN_ENCRYPTION_REQUIRED, codes.CONN_ENCRYPTION_REQUIRED)
-  }
-
   if (resultingOptions.connectionProtector === null && globalThis.process?.env?.LIBP2P_FORCE_PNET != null) { // eslint-disable-line no-undef
     throw new CodeError(messages.ERR_PROTECTOR_REQUIRED, codes.ERR_PROTECTOR_REQUIRED)
   }

test/core/encryption.spec.ts

@@ -1,8 +1,6 @@
 /* eslint-env mocha */
 
 import { webSockets } from '@libp2p/websockets'
-import { expect } from 'aegir/chai'
-import { codes as ErrorCodes } from '../../src/errors.js'
 import { createLibp2p, type Libp2pOptions } from '../../src/index.js'
 import { plaintext } from '../../src/insecure/index.js'
 import { createPeerId } from '../utils/creators/peer.js'
@@ -15,30 +13,6 @@ describe('Connection encryption configuration', () => {
     peerId = await createPeerId()
   })
 
-  it('is required', async () => {
-    const config = {
-      peerId,
-      transports: [
-        webSockets()
-      ]
-    }
-
-    await expect(createLibp2p(config)).to.eventually.be.rejected()
-      .and.to.have.property('code', ErrorCodes.CONN_ENCRYPTION_REQUIRED)
-  })
-
-  it('is required and needs at least one module', async () => {
-    const config = {
-      peerId,
-      transports: [
-        webSockets()
-      ],
-      connectionEncryption: []
-    }
-    await expect(createLibp2p(config)).to.eventually.be.rejected()
-      .and.to.have.property('code', ErrorCodes.CONN_ENCRYPTION_REQUIRED)
-  })
-
   it('can be created', async () => {
     const config: Libp2pOptions = {
       peerId,