Allow to send empty subscription and update version afterward (1.66.x backport)

[ejona86]

Closes #11232

As described in the original issue:

If a CDS update revoke all subscribed resources, all EDS subscriptions will be cancelled.

adjustResourceSubscription issue

The first observation of the istiod logs is,

>>>>> CDS PUSH
2024-06-04T08:30:16.705222Z	info	ads	CDS: PUSH for node:e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default resources:0 size:0B nonce:af2f0bd1-c785-4232-b381-de703b6e3e7d version:2024-06-04T08:30:16Z/7
>>>>> EDS PUSH immediately after CDS
2024-06-04T08:30:16.705384Z	info	ads	EDS: PUSH for node:e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default resources:2 size:395B empty:0 cached:0/2 nonce:cea5b0b2-82d7-4c81-99cc-744ae9a7948e version:2024-06-04T08:30:16Z/7
2024-06-04T08:30:16.705464Z	debug	grpcgen	building lds for e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default with filter:
map[e2e-service-provider.default.svc.cluster.local:{map[e2e-service-provider.default.svc.cluster.local:{}] map[80:{}]}]
2024-06-04T08:30:16.705535Z	info	ads	LDS: PUSH for node:e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default resources:1 size:450B nonce:29cd5728-2464-48b7-ac40-1acb5bd2bc22 version:2024-06-04T08:30:16Z/7
2024-06-04T08:30:16.706144Z	info	ads	RDS: PUSH for node:e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default resources:1 size:4.8kB nonce:1866c85b-4695-4b37-91b0-d9cb844b4181 version:2024-06-04T08:30:16Z/7
2024-06-04T08:30:16.710333Z	debug	ads	ADS:CDS: REQ e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default-1 resources:2 nonce:af2f0bd1-c785-4232-b381-de703b6e3e7d version:2024-06-04T08:30:16Z/7 
2024-06-04T08:30:16.710475Z	debug	ads	ADS:CDS: ACK e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default-1 2024-06-04T08:30:16Z/7 af2f0bd1-c785-4232-b381-de703b6e3e7d
2024-06-04T08:30:16.713459Z	debug	ads	ADS:EDS: REQ e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default-1 resources:1 nonce:2dd9df3c-e64c-4a8e-9787-429e5dcf2719 version:2024-06-04T08:30:14Z/6 
2024-06-04T08:30:16.713508Z	debug	ads	ADS:EDS: REQ e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default-1 Expired nonce received 2dd9df3c-e64c-4a8e-9787-429e5dcf2719, sent cea5b0b2-82d7-4c81-99cc-744ae9a7948e
>>>>>> NO resources:0 REQ log
2024-06-04T08:30:16.718041Z	debug	ads	ADS:LDS: REQ e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default-1 resources:1 nonce:29cd5728-2464-48b7-ac40-1acb5bd2bc22 version:2024-06-04T08:30:16Z/7 
2024-06-04T08:30:16.718084Z	debug	ads	ADS:LDS: ACK e2e-service-consumer-base-5dd4cb9fbf-v6gjk.default-1 2024-06-04T08:30:16Z/7 29cd5728-2464-48b7-ac40-1acb5bd2bc22

If EDS is empty, adjustResourceSubscription does not work.

resourceVersion update issue

If all resources are removed from a type, e.g. EDS, subscribedResourceTypeUrls entry will be also removed. This will prevent nonce being updated from the upstream EDS PUSH.

Backport of #11264