android_host_app_v2_embedding update dependencies and documentation (#164195)

Related to #149836 

Last of the non api 35 references in flutter/flutter for targetSdk and
compileSdk.
`find . -type f -name "build.gradle" | xargs grep -e "targetSdk" | tr -d
'=' | tr -s ' ' | grep -v flutter\.targetSdkVersion | grep -v
engine/src/flutter/third_party/ | grep -v "targetSdk 35"`
`find . -type f -name "build.gradle" | xargs grep -e "compileSdk" | tr
-d '=' | tr -s ' ' | grep -v flutter\.compileSdkVersion | grep -v
engine/src/flutter/third_party/ | grep -v "compileSdk 35"`

rewrite of https://github.com/flutter/flutter/pull/163622 after this
test was updated to run against a newer version of gradle and agp in
https://github.com/flutter/flutter/pull/163849/files#diff-83b6ad7c016bffbb682664eb65c576a7ebf9c312fc60727c0e0e20f5641cbc2aR462

Android-API-And-Related-Versions.md was updated to reflect that after
further investigation that android is using "=" in their documentation
and that the space syntax is discouraged. Equals is setting a property
and space is the equivalent to a function call like `compileSdk(35)` and
assignment is prefered.

The use of equals for proprty assignment also aligns with
https://docs.gradle.org/current/userguide/migrating_from_groovy_to_kotlin_dsl.html#prepare_your_groovy_scripts

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

docs/contributing/Android-API-And-Related-Versions.md

@@ -24,14 +24,14 @@ If the versions chosen are not known by [gradle_utils.dart](https://github.com/f
 ```
 // OK
 android {
-  compileSdk flutter.compileSdkVersion
+  compileSdk = flutter.compileSdkVersion
 }
 ```
 
 ```
 // OK if flutter.compileSdkVersion is not available like in an add to app example.
 android {
-  compileSdk 35
+  compileSdk = 35
 }
 ```
 
@@ -53,14 +53,14 @@ android {
 ```
 // OK
 defaultConfig {
-  targetSdk flutter.targetSdkVersion
+  targetSdk = flutter.targetSdkVersion
 }
 ```
 
 ```
 // OK if flutter.compileSdkVersion is not available like in an add to app example.
 defaultConfig {
-  targetSdk 35
+  targetSdk = 35
 }
 ```