Remove 4.2.7.0 release notes as build was never published (#3345)

The 4.2.7.0 build failed to publish artifacts (see:
https://github.com/FoundationDB/fdb-record-layer/actions/runs/14863133315
and
https://github.com/FoundationDB/fdb-record-layer/actions/runs/14864688455).
As a result, it should not be included in our release notes document.
This combines the release notes information from 4.2.8.0 and 4.2.7.0
into one larger release note for the two combined (catalogued under
4.2.8.0).

Author: alecgrieser

docs/sphinx/source/ReleaseNotes.md

@@ -9,33 +9,6 @@ As the [versioning guide](Versioning.md) details, it cannot always be determined
 
 ### 4.2.8.0
 
-
-<details>
-<summary>
-
-<h4> Build/Test/Documentation/Style Improvements (click to expand) </h4>
-
-</summary>
-
-* Remove jfrog from repository list - [PR #3339](https://github.com/FoundationDB/fdb-record-layer/pull/3339)
-
-</details>
-
-
-**[Full Changelog (4.2.7.0...4.2.8.0)](https://github.com/FoundationDB/fdb-record-layer/compare/4.2.7.0...4.2.8.0)**
-
-#### Mixed Mode Test Results
-
-Mixed mode testing run against the following previous versions:
-
-❌`4.1.6.0`, ❌`4.1.8.0`, ✅`4.1.9.0`, ✅`4.1.10.0`, ✅`4.2.2.0`, ✅`4.2.2.1`, ❌`4.2.3.0`, ❌`4.2.4.0`, ✅`4.2.5.0`, ✅`4.2.6.0`
-
-[See full test run](https://github.com/FoundationDB/fdb-record-layer/actions/runs/14880158619)
-
-
-
-### 4.2.7.0
-
 <h4> Breaking Changes </h4>
 
 * Remove deprecated IndexingByRecords module - [PR #3312](https://github.com/FoundationDB/fdb-record-layer/pull/3312)
@@ -62,19 +35,21 @@ Mixed mode testing run against the following previous versions:
 * Remove jfrog from repository list - [PR #3339](https://github.com/FoundationDB/fdb-record-layer/pull/3339)
 * Fix broken gradle task: testShadowJar - [PR #3320](https://github.com/FoundationDB/fdb-record-layer/pull/3320)
 * Upgrade to gradle 8 - [PR #3316](https://github.com/FoundationDB/fdb-record-layer/pull/3316)
+* Remove jfrog from repository list - [PR #3339](https://github.com/FoundationDB/fdb-record-layer/pull/3339)
 
 </details>
 
 
-**[Full Changelog (4.2.6.0...4.2.7.0)](https://github.com/FoundationDB/fdb-record-layer/compare/4.2.6.0...4.2.7.0)**
+**[Full Changelog (4.2.6.0...4.2.8.0)](https://github.com/FoundationDB/fdb-record-layer/compare/4.2.6.0...4.2.8.0)**
+
 
 #### Mixed Mode Test Results
 
 Mixed mode testing run against the following previous versions:
 
 ❌`4.1.6.0`, ❌`4.1.8.0`, ✅`4.1.9.0`, ✅`4.1.10.0`, ✅`4.2.2.0`, ✅`4.2.2.1`, ❌`4.2.3.0`, ❌`4.2.4.0`, ✅`4.2.5.0`, ✅`4.2.6.0`
 
-[See full test run](https://github.com/FoundationDB/fdb-record-layer/actions/runs/14864688455)
+[See full test run](https://github.com/FoundationDB/fdb-record-layer/actions/runs/14880158619)