Replace java mail with jakarta mail (elastic#40088)

The eclipse foundation has taken over the javax mail dependency, which
resulted in a naming change of the dependency.

Author: spinscale

x-pack/plugin/watcher/build.gradle

@@ -36,7 +36,7 @@ dependencies {
     // watcher deps
     compile 'com.googlecode.owasp-java-html-sanitizer:owasp-java-html-sanitizer:r239'
     compile 'com.google.guava:guava:16.0.1' // needed by watcher for the html sanitizer and security tests for jimfs
-    compile 'com.sun.mail:javax.mail:1.6.2'
+    compile 'com.sun.mail:jakarta.mail:1.6.3'
     // HACK: java 9 removed javax.activation from the default modules, so instead of trying to add modules, which would have
     // to be conditionalized for java 8/9, we pull in the classes directly
     compile 'javax.activation:activation:1.1.1'

x-pack/plugin/watcher/licenses/jakarta.mail-1.6.3.jar.sha1

@@ -0,0 +1 @@
+787e007e377223bba85a33599d3da416c135f99b

x-pack/plugin/watcher/licenses/jakarta.mail-LICENSE.txt

@@ -0,0 +1,50 @@
+# Notices for Eclipse Project for JavaMail
+
+This content is produced and maintained by the Eclipse Project for JavaMail
+project.
+
+* Project home: https://projects.eclipse.org/projects/ee4j.javamail
+
+## Trademarks
+
+Eclipse Project for JavaMail is a trademark of the Eclipse Foundation.
+
+## Copyright
+
+All content is the property of the respective authors or their employers. For
+more information regarding authorship of content, please consult the listed
+source code repository logs.
+
+## Declared Project Licenses
+
+This program and the accompanying materials are made available under the terms
+of the Eclipse Public License v. 2.0 which is available at
+http://www.eclipse.org/legal/epl-2.0. This Source Code may also be made
+available under the following Secondary Licenses when the conditions for such
+availability set forth in the Eclipse Public License v. 2.0 are satisfied: GNU
+General Public License, version 2 with the GNU Classpath Exception which is
+available at https://www.gnu.org/software/classpath/license.html.
+
+SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+
+## Source Code
+
+The project maintains the following source code repositories:
+
+* https://github.com/eclipse-ee4j/javamail
+
+## Third-party Content
+
+This project leverages the following third party content.
+
+None
+
+## Cryptography
+
+Content may contain encryption software. The country in which you are currently
+may have restrictions on the import, possession, and use, and/or re-export to
+another country, of encryption software. BEFORE using any encryption software,
+please check the country's laws, regulations and policies concerning the import,
+possession, or use, and re-export of encryption software, to see if this is
+permitted.
+