Migrate to max line length of 100

This commit moves the checkstyle rule of max line length from 140
characters to 100 characters. We whitelist all existing violations and
will address them in follow-ups.

Relates #23623

buildSrc/src/main/resources/checkstyle.xml

@@ -22,7 +22,7 @@
       suppress the check there but enforce it everywhere else. This prevents the list from getting longer even if it is
       unfair. -->
     <module name="LineLength">
-      <property name="max" value="140"/>
+      <property name="max" value="100"/>
     </module>
 
     <module name="AvoidStarImport" />