Remove dependency management for Micrometer Context Propagation

It's now managed as part of Micrometer's bom so we no longer need to
manage it separately (and our separate management was being overriden
by Micrometer's bom anyway).

Closes gh-45852

spring-boot-project/spring-boot-parent/build.gradle

@@ -137,13 +137,6 @@ bom {
 			]
 		}
 	}
-	library("Micrometer Context Propagation", "1.0.5") {
-		group("io.micrometer") {
-			modules = [
-				"context-propagation"
-			]
-		}
-	}
 	library("MockK", "1.13.5") {
 		group("io.mockk") {
 			modules = [