Fix bundle outdated --groups to actually group output

[nevinera]

Purpose

Update bundle outdated --groups to produce its table of output actually sorted by group.

Analysis

print_indented unconditionally sorted table rows by gem name, discarding the group clustering that --groups had already computed, so --groups produced output identical to plain outdated (#9333). Skip that re-sort when a --group/--groups option is active, since specs_for_outdated_check already sorts by name and group_by preserves that order within each group.

What was the end-user or developer problem that led to this PR?

A (correct) observation in #9333 that bundle outdated --groups was not actually grouping at all.

What is your fix for the problem, implemented in this PR?

• Update the existing test on this to assert a more obviously failing result - because listing the gems alphabetically also resulted in them being accidentally "grouped"
• Add a sort = true second positional parameter to print_indented!, which controls whether to sort its results before printing
• in print_gems_table, determine whether to sort based on the options_include_groups attr, which is true if --groups or --group foo is supplied.

Make sure the following tasks are checked

• Describe the problem / feature
• Write tests for features and bug fixes
• Write code to solve the problem
• Make sure you follow the current code style and write meaningful commit messages without tags