Monitor.Slis: set 1.0.0-beta.2 release date and drop empty CHANGELOG sections (Azure#59579)

Release pipeline build 6379367 failed with:
- Entry has no release date set
- Empty 'Bugs Fixed' and 'Other Changes' sections

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: saleelpk

sdk/monitor/Azure.ResourceManager.Monitor.Slis/CHANGELOG.md

@@ -1,6 +1,6 @@
 # Release History
 
-## 1.0.0-beta.2 (Unreleased)
+## 1.0.0-beta.2 (2026-06-01)
 
 ### Features Added
 
@@ -14,10 +14,6 @@
 - Changed `SliConditionOperator` wire values from symbolic operators to named operators: `==` to `eq`, `!=` to `ne`, `>` to `gt`, `>=` to `gte`, `<` to `lt`, `<=` to `lte`, `@in` to `in`, `!in` to `notin`, `!contains` to `notcontains`, and `!startswith` to `notstartswith`.
 - Changed `WindowUptimeCriteriaComparator` wire values from symbolic operators to named operators: `>` to `gt`, `>=` to `gte`, `<` to `lt`, and `<=` to `lte`.
 
-### Bugs Fixed
-
-### Other Changes
-
 ## 1.0.0-beta.1 (2026-04-22)
 
 ### Features Added