This commit reworks 40d8726d as it has introduced an unfortunate side
effect for those who are using a starter with optional starter
dependencies.

`spring-boot-starter-web` defines the json and the tomcat starter. The
latter is part of a set of starters that do not bring the base starter
and the former can be excluded to use gson rather than jackson.

When such arrangement happens, spring-boot-starter-web no longer defines
the base starter (and therefore doesn't bring the core dependencies
that Spring Boot needs to bootstrap).

This commit reviews the starters that define optional starters and
reintroduce the base starter.

Closes gh-14076