Added tree_height.cpp in dynamic_programming directory

[mann2108]

Description of Change

Added finding the height of the valid tree in O(n) using bottom - up dp approach.
where n is a number of nodes.
A valid tree contain exactly n-1 edges when n is number of nodes.
Sample Input: -
4
1 2
1 3
2 3

Hence the height of the tree is 3

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass
• Relevant documentation/comments is changed or added
• PR title follows semantic commit guidelines
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Notes:

[mann2108]

Four errors found in https://github.com/TheAlgorithms/C-Plus-Plus/actions

@cclauss Its fixed.

[bhaumikmistry]

@cclauss Any idea what can we do to add tests for incoming checks, we can tests the working for this by just looking at it!!

[cclauss]

There are multiple unit test frameworks for C++. So someone who really knows the current state of C++ (i.e. not me) needs to pick one of them and then I can help with the GitHub Actions to enforce the rule that every new submission must have tests and pass them. TheAlgorithms/Python does this and pytest currently runs >500 tests on every submission. If you want to proceed, please open a new issue.

[mann2108]

@cclauss Should we merge this PR?

[cclauss]

It has my approval but let's let @bhaumikmistry decide.

[poyea]

LGTM. Can be merged at any time.