[ANE-2718] fix(scala): prefer MiniDependencyTreePlugin over explicit DependencyTreePlugin

[saramaebee]

Summary

This PR fixes an issue where fossa analyze fails to detect deep (transitive) dependencies on sbt 1.4+ projects that have an explicit addDependencyTreePlugin in their plugins.sbt.

Changes:

• Reorder pattern matching in findProjects to prefer MiniDependencyTreePlugin (sbt 1.4+ built-in) over explicitly configured DependencyTreePlugin
• Extract pure detectDependencyPlugins function for testability
• Add comprehensive unit tests for plugin detection scenarios

Root Cause

The sbt dependencyBrowseTreeHTML command has different casing requirements across versions:

• sbt < 1.4: Uses lowercase dependencyBrowseTreeHtml
• sbt >= 1.4: Uses uppercase dependencyBrowseTreeHTML

When a project has both the built-in MiniDependencyTreePlugin (sbt 1.4+) AND an explicit DependencyTreePlugin (via addDependencyTreePlugin), FOSSA was prioritizing the explicit plugin path, which uses the lowercase command - causing failures on sbt 1.4+.

Reproduction

Environment:

• sbt: 1.11.5 (or any sbt 1.4+)
• Plugin: addDependencyTreePlugin explicitly in plugins.sbt

Steps to reproduce the issue:

# 1. Create a simple sbt project with explicit plugin
mkdir repro && cd repro
echo 'addDependencyTreePlugin' > project/plugins.sbt
echo 'scalaVersion := "3.3.4"
libraryDependencies += "org.typelevel" %% "cats-core" % "2.12.0"' > build.sbt

# 2. Verify the casing issue exists
sbt "dependencyBrowseTreeHtml"   # FAILS on sbt 1.4+
sbt "dependencyBrowseTreeHTML"   # WORKS on sbt 1.4+
sbt "dependencyTree"             # WORKS (what the fix uses)

# 3. Run fossa analyze and observe partial results
fossa analyze -o --debug 2>&1 | grep -i "GraphBreadth"
# Shows: GraphBreadth: Partial (missing transitive deps)

Test Plan

1. Confirm broken behavior on master

git checkout master
cabal build
fossa analyze -o --debug  # in a sbt 1.4+ project with explicit addDependencyTreePlugin
# Observe: GraphBreadth: Partial, ~7 direct deps only

2. Checkout PR branch and rebuild

git checkout fix/sbt-dependency-tree-plugin-priority
cabal build

3. Verify fix

fossa analyze -o --debug  # same sbt project
# Observe: GraphBreadth: complete, 26+ deps with transitives

4. Unit tests

cabal test unit-tests --test-option="--match=Scala"
# All 5 plugin detection tests pass

Expected results comparison:

Metric	Before (master)	After (this PR)
GraphBreadth	Partial ❌	complete ✅
Dependencies	~7 direct only	26+ with transitives
Status	Warnings	Succeeded