Solucionado
Após gerar a senha 123456 criptografada e alterar o arquivo data.sql, tento logar na aplicação e recebo esse erro:
2020-05-21 12:07:35.540 ERROR 12676 --- [nio-8080-exec-4] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Filter execution threw an exception] with root cause
java.lang.StackOverflowError: null at br.com.alura.forum.modelo.Usuario.getPassword(Usuario.java:104) ~[classes/:na]
o método getPassword da minha classe Usuario estava retornando this.password ao invés de retornar this.senha. Ao corrigir, surgiu novo erro:
java.lang.IllegalArgumentException: There is no PasswordEncoder mapped for the id "null" at org.springframework.security.crypto.password.DelegatingPasswordEncoder$UnmappedIdPasswordEncoder.matches(DelegatingPasswordEncoder.java:250) ~[spring-security-core-5.3.2.RELEASE.jar:5.3.2.RELEASE] at org.springframework.security.crypto.password.DelegatingPasswordEncoder.matches(DelegatingPasswordEncoder.java:198) ~[spring-security-core-5.3.2.RELEASE.jar:5.3.2.RELEASE] at org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter$LazyPasswordEncoder.matches(WebSecurityConfigurerAdapter.java:604) ~[spring-security-config-5.3.2.RELEASE.jar:5.3.2.RELEASE]
Ok. Foi erro meu. Faltou ajustar o passwordEncoder.